This question already has answers here:
Adjust a div's height/width by dragging its left/top border without jQuery draggable?
(2 answers)
Closed 7 years ago.
Is it possible to make <select>'s height adjustable by the user? Simply by dragging the bottom of the expanded list.
Cross browser, you can't drag native drop-down boxes, but here is one suggestion how one can do.
Edit: But when the size property is set (size="2") you can, kind of. By elaborating with the option height and the amount of item, you might achieve something useful.
The select has a invisible area outside its bottom which make it resizeable. You can also click inside the select and resize, though the list drops down every second time.
Resources:
Adjust a div's height/width by dragging its left/top border without jQuery draggable?
jQuery draggable option elements
$(document).ready(function(){
$('#drag').on('mousedown', function(e){
var $dragable = $(this),
start = $dragable.height(),
pY = e.pageY;
$(document).on('mouseup', function(e){
$(document).off('mouseup').off('mousemove');
});
$(document).on('mousemove', function(me){
var my = (me.pageY - pY);
$dragable.css({
height: start + my,
});
});
});
$('#drag2').on('mousedown', function(e){
var $dragable = $(this),
start = $dragable.height(),
pY = e.pageY;
$(document).on('mouseup', function(e){
$(document).off('mouseup').off('mousemove');
});
$(document).on('mousemove', function(me){
var my = (me.pageY - pY);
$dragable.css({
height: start + my,
});
});
});
});
body {
margin: 30px;
}
div{
position: relative;
display: inline-block;
cursor: row-resize;
height: 30px;
padding-bottom: 10px;
}
select{
position: relative;
height: 100%;
vertical-align: top;
}
option {
padding: 5px 15px;
height: 25%; /* sizable when size property is set to more than 1 */
}
#drag2 {
margin-left: 20px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="wrap">
<div id="drag">
<select>
<option>nr1</option>
<option>nr2</option>
<option>nr3</option>
<option>nr4</option>
</select>
</div>
<div id="drag2">
<select size="2">
<option>nr1</option>
<option>nr2</option>
<option>nr3</option>
<option>nr4</option>
</select>
</div>
</div>
Many textarea resizer js pluggins should work with select too...
I'm wondering if there is a way to have a div, absolutely positioned, hover over the border of the iframe that div is in. Can this be done?
My case:
I have an iframe with a list of files in it, on the right end of each file there is a button. I want to have a div-popup with some functions like a contextmenu. But because this button is at the edge of the iframe the absolutely positioned div is put behind/outside the iframe viewport. I want it to overlay in the rest of my document, outside the iframe.
<iframe width="100" height="100">
div would be in here, say 300 x 100 px.
</iframe>
overlayed div should be visible here as well, basically the div should overlay the iframe.
Well, technically you can't do that. However, if you hijack the events in the iframe, you can recreate the context menu in the main window and use the relative position of the div within the iframe + the absolute position of the iframe itself.
So, to sum up, the context menu can be outside the iframe, and manipulated by the events from within the iframe.
Let me show you how it can be done. I don't have your code, so I'm just making a very crude proof of concept. :)
Example | Code
HTML
<iframe id='my_frame'></iframe>
<div id='copy_to_frame'>
<ul id='files_list'>
<li>data.dat</li>
<li>manual.html</li>
<li>readme.txt</li>
<li>model1.obj</li>
<li>human_model.obj</li>
</ul>
</div>
<div class='context_menu'>
<ul>
<li>Delete</li><li>Open</li><li>Move</li><li>Copy</li>
</ul>
</div>
Javascript
//Declare the necessary variables, good practice
var frame = $("#my_frame"),
frame_contents = frame.contents(),
frame_body = frame_contents .find("body"),
copy_list = $("#copy_to_frame"),
context_menu = $(".context_menu");
var bInside = false;
//Fill the iframe with a list
frame_body.html(copy_list.html());
copy_list.hide();
paint();
//Attach event handler for context menu popup etc.
$("#files_list li", frame_body).click(function(e){
var $this = $(this);
var rel_x = $this.position().left + $this.outerWidth() + 5,
rel_y = $this.position().top + $this.outerHeight()/2 - context_menu.outerHeight()/2 - frame_body.scrollTop(),
abs_x = frame.offset().left,
abs_y = frame.offset().top;
e.stopPropagation();
context_menu.css({
top: rel_y + abs_y,
left: rel_x + abs_x
});
//Show the context menu in this window
context_menu.show();
paint($this);
});
//Hide when clicking outside the context menu
$(document).add(frame_body).click(function(){
if(!bInside){
context_menu.hide();
paint();
}
});
//Determine if mouse is inside context menu
context_menu.mouseenter(function(){
bInside = true;
}).mouseleave(function(){
bInside = false;
});
function paint(el){
$("#files_list li", frame_body).css({
"background-color": "white",
"border": "1px solid transparent"
});
if(el){
el.css({
"background-color": "#ddecfd",
"border": "1px solid #7da2ce"
});
}
}
CSS
#my_frame{
position: absolute;
border: 1px solid gray;
width: 200px;
height: 100px;
top: 50%; left: 50%;
margin-top: -62.5px;
margin-left: -100px;
z-index: 1;
}
.context_menu{
display: none;
position: absolute;
top: 0;
left: 0;
background-color: white;
z-index: 2;
}
.context_menu ul{
border: 1px solid black;
border-right: 0;
display: inline-block;
}
.context_menu li{
display: inline-block;
border-right: 1px solid black;
padding: 2px;
text-align: center;
margin: 0px;
cursor: default;
}
.context_menu li:hover{
background-color: lightgray;
}
This is a bit of a guess based on the minimal information that was provided, but...
You can manipulate the contents of an <iframe> from within the parent document using jQuery, like so:
$('#myFrame').contents().find('a').click(function() { /*...*/ });
This allows you to detect when the user has clicked inside the <iframe>. Then you can work out where to position your overlay <div>.
Your overlay <div> will need to have position: fixed set. You can use jQuery's .offset() method to get the coordinates of the <iframe> and the link that was clicked inside the <iframe>. You can use these two values to calculate where to position the overlay <div> in the parent document. For example, to position the overlay to the left of the <iframe> and on the same vertical level as the link that was clicked you can do this:
$('#overlayDiv')
.offset({
left: $('#myFrame').offset().left - $('#overlayDiv').width(),
top: $('#myFrame').offset().top + $(this).offset().top
})
See this fiddle for a basic example of how it could work: http://jsfiddle.net/Gxd3M/2/
(Note that this assumes that the contents of the parent document and the iframe both come from the same server, i.e. they have the same origin.)
This question already has answers here:
Fixed page header overlaps in-page anchors
(38 answers)
Closed 7 years ago.
I am trying to clean up the way my anchors work. I have a header that is fixed to the top of the page, so when you link to an anchor elsewhere in the page, the page jumps so the anchor is at the top of the page, leaving the content behind the fixed header (I hope that makes sense). I need a way to offset the anchor by the 25px from the height of the header. I would prefer HTML or CSS, but Javascript would be acceptable as well.
You could just use CSS without any javascript.
Give your anchor a class:
<a class="anchor" id="top"></a>
You can then position the anchor an offset higher or lower than where it actually appears on the page, by making it a block element and relatively positioning it. -250px will position the anchor up 250px
a.anchor {
display: block;
position: relative;
top: -250px;
visibility: hidden;
}
I found this solution:
<a name="myanchor">
<h1 style="padding-top: 40px; margin-top: -40px;">My anchor</h1>
</a>
This doesn't create any gap in the content and anchor links works really nice.
I was looking for a solution to this as well. In my case, it was pretty easy.
I have a list menu with all the links:
<ul>
<li>one</li>
<li>two</li>
<li>three</li>
<li>four</li>
</ul>
And below that the headings where it should go to.
<h3>one</h3>
<p>text here</p>
<h3>two</h3>
<p>text here</p>
<h3>three</h3>
<p>text here</p>
<h3>four</h3>
<p>text here</p>
Now because I have a fixed menu at the top of my page I can't just make it go to my tag because that would be behind the menu.
Instead, I put a span tag inside my tag with the proper id.
<h3><span id="one"></span>one</h3>
Now use 2 lines of CSS to position them properly.
h3{ position:relative; }
h3 span{ position:absolute; top:-200px;}
Change the top value to match the height of your fixed header (or more).
Now I assume this would work with other elements as well.
FWIW this worked for me:
[id]::before {
content: '';
display: block;
height: 75px;
margin-top: -75px;
visibility: hidden;
}
As this is a concern of presentation, a pure CSS solution would be ideal. However, this question was posed in 2012, and although relative positioning / negative margin solutions have been suggested, these approaches seem rather hacky, create potential flow issues, and cannot respond dynamically to changes in the DOM / viewport.
With that in mind I believe that using JavaScript is still (February 2017) the best approach. Below is a vanilla-JS solution which will respond both to anchor clicks and resolve the page hash on load (See JSFiddle). Modify the .getFixedOffset() method if dynamic calculations are required. If you're using jQuery, here's a modified solution with better event delegation and smooth scrolling.
(function(document, history, location) {
var HISTORY_SUPPORT = !!(history && history.pushState);
var anchorScrolls = {
ANCHOR_REGEX: /^#[^ ]+$/,
OFFSET_HEIGHT_PX: 50,
/**
* Establish events, and fix initial scroll position if a hash is provided.
*/
init: function() {
this.scrollToCurrent();
window.addEventListener('hashchange', this.scrollToCurrent.bind(this));
document.body.addEventListener('click', this.delegateAnchors.bind(this));
},
/**
* Return the offset amount to deduct from the normal scroll position.
* Modify as appropriate to allow for dynamic calculations
*/
getFixedOffset: function() {
return this.OFFSET_HEIGHT_PX;
},
/**
* If the provided href is an anchor which resolves to an element on the
* page, scroll to it.
* #param {String} href
* #return {Boolean} - Was the href an anchor.
*/
scrollIfAnchor: function(href, pushToHistory) {
var match, rect, anchorOffset;
if(!this.ANCHOR_REGEX.test(href)) {
return false;
}
match = document.getElementById(href.slice(1));
if(match) {
rect = match.getBoundingClientRect();
anchorOffset = window.pageYOffset + rect.top - this.getFixedOffset();
window.scrollTo(window.pageXOffset, anchorOffset);
// Add the state to history as-per normal anchor links
if(HISTORY_SUPPORT && pushToHistory) {
history.pushState({}, document.title, location.pathname + href);
}
}
return !!match;
},
/**
* Attempt to scroll to the current location's hash.
*/
scrollToCurrent: function() {
this.scrollIfAnchor(window.location.hash);
},
/**
* If the click event's target was an anchor, fix the scroll position.
*/
delegateAnchors: function(e) {
var elem = e.target;
if(
elem.nodeName === 'A' &&
this.scrollIfAnchor(elem.getAttribute('href'), true)
) {
e.preventDefault();
}
}
};
window.addEventListener(
'DOMContentLoaded', anchorScrolls.init.bind(anchorScrolls)
);
})(window.document, window.history, window.location);
Pure css solution inspired by Alexander Savin:
a[name] {
padding-top: 40px;
margin-top: -40px;
display: inline-block; /* required for webkit browsers */
}
Optionally you may want to add the following if the target is still off the screen:
vertical-align: top;
My solution combines the target and before selectors for our CMS. Other techniques don't account for text in the anchor. Adjust the height and the negative margin to the offset you need...
:target::before {
content: '';
display: block;
height: 180px;
margin-top: -180px;
}
This takes many elements from previous answers and combines into a tiny (194 bytes minified) anonymous jQuery function. Adjust fixedElementHeight for the height of your menu or blocking element.
(function($, window) {
var adjustAnchor = function() {
var $anchor = $(':target'),
fixedElementHeight = 100;
if ($anchor.length > 0) {
$('html, body')
.stop()
.animate({
scrollTop: $anchor.offset().top - fixedElementHeight
}, 200);
}
};
$(window).on('hashchange load', function() {
adjustAnchor();
});
})(jQuery, window);
If you don't like the animation, replace
$('html, body')
.stop()
.animate({
scrollTop: $anchor.offset().top - fixedElementHeight
}, 200);
with:
window.scrollTo(0, $anchor.offset().top - fixedElementHeight);
Uglified version:
!function(o,n){var t=function(){var n=o(":target"),t=100;n.length>0&&o("html, body").stop().animate({scrollTop:n.offset().top-t},200)};o(n).on("hashchange load",function(){t()})}(jQuery,window);
For modern browsers, just add the CSS3 :target selector to the page. This will apply to all the anchors automatically.
:target {
display: block;
position: relative;
top: -100px;
visibility: hidden;
}
You can do it without js and without altering html. It´s css-only.
a[id]::before {
content: '';
display: block;
height: 50px;
margin: -30px 0 0;
}
That will append a pseudo-element before every a-tag with an id. Adjust values to match the height of your header.
I had been facing a similar issue, unfortunately after implementing all the solutions above, I came to the following conclusion.
My inner elements had a fragile CSS structure and implementing a position relative / absolute play, was completely breaking the page design.
CSS is not my strong suit.
I wrote this simple scrolling js, that accounts for the offset caused due to the header and relocated the div about 125 pixels below. Please use it as you see fit.
The HTML
<div id="#anchor"></div> <!-- #anchor here is the anchor tag which is on your URL -->
The JavaScript
$(function() {
$('a[href*=#]:not([href=#])').click(function() {
if (location.pathname.replace(/^\//,'') == this.pathname.replace(/^\//,'')
&& location.hostname == this.hostname) {
var target = $(this.hash);
target = target.length ? target : $('[name=' + this.hash.slice(1) +']');
if (target.length) {
$('html,body').animate({
scrollTop: target.offset().top - 125 //offsets for fixed header
}, 1000);
return false;
}
}
});
//Executed on page load with URL containing an anchor tag.
if($(location.href.split("#")[1])) {
var target = $('#'+location.href.split("#")[1]);
if (target.length) {
$('html,body').animate({
scrollTop: target.offset().top - 125 //offset height of header here too.
}, 1000);
return false;
}
}
});
See a live implementation here.
For the same issue, I used an easy solution : put a padding-top of 40px on each anchor.
As #moeffju suggests, this can be achieved with CSS. The issue I ran into (which I'm surprised I haven't seen discussed) is the trick of overlapping previous elements with padding or a transparent border prevents hover and click actions at the bottom of those sections because the following one comes higher in the z-order.
The best fix I found was to place section content in a div that is at z-index: 1:
// Apply to elements that serve as anchors
.offset-anchor {
border-top: 75px solid transparent;
margin: -75px 0 0;
-webkit-background-clip: padding-box;
-moz-background-clip: padding;
background-clip: padding-box;
}
// Because offset-anchor causes sections to overlap the bottom of previous ones,
// we need to put content higher so links aren't blocked by the transparent border.
.container {
position: relative;
z-index: 1;
}
Solutions with changing position property are not always possible (it can destroy layout) therefore I suggest this:
HTML:
<a id="top">Anchor</a>
CSS:
#top {
margin-top: -250px;
padding-top: 250px;
}
Use this:
<a id="top"> </a>
to minimize overlapping, and set font-size to 1px. Empty anchor will not work in some browsers.
Borrowing some of the code from an answer given at this link (no author is specified), you can include a nice smooth-scroll effect to the anchor, while making it stop at -60px above the anchor, fitting nicely underneath the fixed bootstrap navigation bar (requires jQuery):
$(".dropdown-menu a[href^='#']").on('click', function(e) {
// prevent default anchor click behavior
e.preventDefault();
// animate
$('html, body').animate({
scrollTop: $(this.hash).offset().top - 60
}, 300, function(){
});
});
The above methods don't work very well if your anchor is a table element or within a table (row or cell).
I had to use javascript and bind to the window hashchange event to work around this (demo):
function moveUnderNav() {
var $el, h = window.location.hash;
if (h) {
$el = $(h);
if ($el.length && $el.closest('table').length) {
$('body').scrollTop( $el.closest('table, tr').position().top - 26 );
}
}
}
$(window)
.load(function () {
moveUnderNav();
})
.on('hashchange', function () {
moveUnderNav();
});
* Note: The hashchange event is not available in all browsers.
You can achieve this without an ID using the a[name]:not([href]) css selector. This simply looks for links with a name and no href e.g. <a name="anc1"></a>
An example rule might be:
a[name]:not([href]){
display: block;
position: relative;
top: -100px;
visibility: hidden;
}
Instead of having a fixed-position navbar which is underlapped by the rest of the content of the page (with the whole page body being scrollable), consider instead having a non-scrollable body with a static navbar and then having the page content in an absolutely-positioned scrollable div below.
That is, have HTML like this...
<div class="static-navbar">NAVBAR</div>
<div class="scrollable-content">
<p>Bla bla bla</p>
<p>Yadda yadda yadda</p>
<p>Mary had a little lamb</p>
<h2 id="stuff-i-want-to-link-to">Stuff</h2>
<p>More nonsense</p>
</div>
... and CSS like this:
.static-navbar {
height: 100px;
}
.scrollable-content {
position: absolute;
top: 100px;
bottom: 0;
overflow-y: scroll;
width: 100%;
}
There is one significant downside to this approach, however, which is that while an element from the page header is focused, the user will not be able to scroll the page using the keyboard (e.g. via the up and down arrows or the Page Up and Page Down keys).
Here's a JSFiddle demonstrating this in action.
This was inspired by the answer by Shouvik - same concept as his, only the size of the fixed header isn't hard coded. As long as your fixed header is in the first header node, this should "just work"
/*jslint browser: true, plusplus: true, regexp: true */
function anchorScroll(fragment) {
"use strict";
var amount, ttarget;
amount = $('header').height();
ttarget = $('#' + fragment);
$('html,body').animate({ scrollTop: ttarget.offset().top - amount }, 250);
return false;
}
function outsideToHash() {
"use strict";
var fragment;
if (window.location.hash) {
fragment = window.location.hash.substring(1);
anchorScroll(fragment);
}
}
function insideToHash(nnode) {
"use strict";
var fragment;
fragment = $(nnode).attr('href').substring(1);
anchorScroll(fragment);
}
$(document).ready(function () {
"use strict";
$("a[href^='#']").bind('click', function () {insideToHash(this); });
outsideToHash();
});
I'm facing this problem in a TYPO3 website, where all "Content Elements" are wrapped with something like:
<div id="c1234" class="contentElement">...</div>
and i changed the rendering so it renders like this:
<div id="c1234" class="anchor"></div>
<div class="contentElement">...</div>
And this CSS:
.anchor{
position: relative;
top: -50px;
}
The fixed topbar being 40px high, now the anchors work again and start 10px under the topbar.
Only drawback of this technique is you can no longer use :target.
Adding to Ziav's answer (with thanks to Alexander Savin), I need to be using the old-school <a name="...">...</a> as we're using <div id="...">...</div> for another purpose in our code. I had some display issues using display: inline-block -- the first line of every <p> element was turning out to be slightly right-indented (on both Webkit and Firefox browsers). I ended up trying other display values and display: table-caption works perfectly for me.
.anchor {
padding-top: 60px;
margin-top: -60px;
display: table-caption;
}
I added 40px-height .vspace element holding the anchor before each of my h1 elements.
<div class="vspace" id="gherkin"></div>
<div class="page-header">
<h1>Gherkin</h1>
</div>
In the CSS:
.vspace { height: 40px;}
It's working great and the space is not chocking.
how about hidden span tags with linkable IDs that provide the height of the navbar:
#head1 {
padding-top: 60px;
height: 0px;
visibility: hidden;
}
<span class="head1">somecontent</span>
<h5 id="headline1">This Headline is not obscured</h5>
heres the fiddle: http://jsfiddle.net/N6f2f/7
You can also add an anchor with follow attr:
(text-indent:-99999px;)
visibility: hidden;
position:absolute;
top:-80px;
and give the parent container a position relative.
Works perfect for me.
A further twist to the excellent answer from #Jan is to incorporate this into the #uberbar fixed header, which uses jQuery (or MooTools). (http://davidwalsh.name/persistent-header-opacity)
I've tweaked the code so the the top of the content is always below not under the fixed header and also added the anchors from #Jan again making sure that the anchors are always positioned below the fixed header.
The CSS:
#uberbar {
border-bottom:1px solid #0000cc;
position:fixed;
top:0;
left:0;
z-index:2000;
width:100%;
}
a.anchor {
display: block;
position: relative;
visibility: hidden;
}
The jQuery (including tweaks to both the #uberbar and the anchor approaches:
<script type="text/javascript">
$(document).ready(function() {
(function() {
//settings
var fadeSpeed = 200, fadeTo = 0.85, topDistance = 30;
var topbarME = function() { $('#uberbar').fadeTo(fadeSpeed,1); }, topbarML = function() { $('#uberbar').fadeTo(fadeSpeed,fadeTo); };
var inside = false;
//do
$(window).scroll(function() {
position = $(window).scrollTop();
if(position > topDistance && !inside) {
//add events
topbarML();
$('#uberbar').bind('mouseenter',topbarME);
$('#uberbar').bind('mouseleave',topbarML);
inside = true;
}
else if (position < topDistance){
topbarME();
$('#uberbar').unbind('mouseenter',topbarME);
$('#uberbar').unbind('mouseleave',topbarML);
inside = false;
}
});
$('#content').css({'margin-top': $('#uberbar').outerHeight(true)});
$('a.anchor').css({'top': - $('#uberbar').outerHeight(true)});
})();
});
</script>
And finally the HTML:
<div id="uberbar">
<!--CONTENT OF FIXED HEADER-->
</div>
....
<div id="content">
<!--MAIN CONTENT-->
....
<a class="anchor" id="anchor1"></a>
....
<a class="anchor" id="anchor2"></a>
....
</div>
Maybe this is useful to somebody who likes the #uberbar fading dixed header!
#AlexanderSavin's solution works great in WebKit browsers for me.
I additionally had to use :target pseudo-class which applies style to the selected anchor to adjust padding in FF, Opera & IE9:
a:target {
padding-top: 40px
}
Note that this style is not for Chrome / Safari so you'll probably have to use css-hacks, conditional comments etc.
Also I'd like to notice that Alexander's solution works due to the fact that targeted element is inline. If you don't want link you could simply change display property:
<div id="myanchor" style="display: inline">
<h1 style="padding-top: 40px; margin-top: -40px;">My anchor</h1>
</div>
Here's the solution that we use on our site. Adjust the headerHeight variable to whatever your header height is. Add the js-scroll class to the anchor that should scroll on click.
// SCROLL ON CLICK
// --------------------------------------------------------------------------
$('.js-scroll').click(function(){
var headerHeight = 60;
$('html, body').animate({
scrollTop: $( $.attr(this, 'href') ).offset().top - headerHeight
}, 500);
return false;
});
I ran into this same issue and ended up handling the click events manually, like:
$('#mynav a').click(() ->
$('html, body').animate({
scrollTop: $($(this).attr('href')).offset().top - 40
}, 200
return false
)
Scroll animation optional, of course.
Please have a look at this fiddle: http://fiddle.jshell.net/ikmac/q7gkx
Use this link to test in the browser: http://fiddle.jshell.net/ikmac/q7gkx/show/
HTML:
<div class="nav">
test1
test2
test3
</div>
<div id="test1" class="test">test1</div>
<div id="test2" class="test">test2</div>
<div id="test3" class="test">test3</div>
CSS:
.nav {
position: fixed;
top: 20px;
left: 0;
width: 100%;
height: 20px;
background: #000;
}
.nav a {
float: left;
font-size: 20px;
color: #fff;
}
#test1 {
margin-top: 1000px;
height: 1000px;
background: red;
}
#test2 {
height: 1000px;
background: blue;
}
#test3 {
height: 1000px;
background: green;
}
This is what happens in Safari on iOS 5.0 (4.3 doesn't support position fixed):
The first time I click on one of the anchors the page jumps to the correct anchor. After that I cannot click one of the other links anymore. When I scroll up or down a bit the links become clickable again.
All other desktop browsers behave fine.
Does anyone ever had this issue before or knows how to fix it?
I have that problem aswell. And I kind of half solved it by letting javascript do the scrolling of the nav when a nav anchor is clicked. And because normal touch-scrolling does not give an event until the finger lets go of the screen, I use position:fixed which makes the touch-scrolling nicer than javascript can, see apples dev-site.
It is not the ultimate solution, but in my opinion it is better than not working at all. This script also checks the width of the window to make sure that it only applies this to smaller screens, well, devices.
Here is my code, and if you find it useful, make it better or find a better solution, please share :)
/* NAV POSITION */
var specScroll = false; // If special scrolling is needed
/* Check what kind of position to use.*/
(function navPos() {
var width = checkWidth();
if (width <= 480 || navigator.userAgent.match(/iPad/i) != null) {
specScroll = true;
}else{
specScroll = false;
window.onscroll = NaN;
}
})();
$(window).resize( function(){ navPos(); } ); // After resizing, check what to use again.
/* When clicking one of the nav anchors */
$(function() {
$('a').bind('click',function(e){
var $anchor = $(this);
if(specScroll){
$('#nav').css('position', "absolute");
window.onscroll = anchorScroll;
}
$('html, body').stop().animate({
scrollTop: $($anchor.attr('href')).offset().top
}, 700,'easeOutExpo', function(){
if(specScroll){setTimeout("window.onscroll = touchScroll;", 100);}
// the set timeout is needed for not overriding the clickability of the anchors after anchor-scrolling.
});
e.preventDefault();
});
});
/* While the user clicks and anchors in nav */
function anchorScroll() { $('#nav').css('top', window.pageYOffset); }
/* the first time the user scrolls by touch and lift the finger from screen */
function touchScroll() {
$('#nav').css('position', 'fixed');
$('#nav').css('top', 0);
window.onscroll = NaN;
}
/* CHECK WIDTH OF WINDOW */
function checkWidth() {
myWidth = 0;
if( typeof( window.innerWidth ) == 'number' ) {
myWidth = window.innerWidth; //Non-IE
} else if( document.documentElement && ( document.documentElement.clientWidth ) ) {
myWidth = document.documentElement.clientWidth; //IE 6+ in 'standards compliant mode'
} else if( document.body && ( document.body.clientWidth ) ) {
myWidth = document.body.clientWidth; //IE 4 compatible
}
return myWidth;
}
I use this solution on a project page, try it out: dare.niklasek.se
I ran into the same issue using a fixed position navigation that scrolls the user around the page using jQuery animation. What I found is that even though the fixed position element is visible at the new position, inspecting it with js reports that it is still back in the original position until the user moves the screen manually. Until then, even though the nav is there visually, it can't be touched in order to interact with it. More information and demo here: http://bit.ly/ios5fixedBug
I've searched around quite a bit and I'm fairly certain this doesn't exist, I'm mainly looking to confirm that. What I'd like to do is have a div that makes everything behind it transparent -- similar to what canvas' destination-out compositing option does.
For a little more context, here's the situation. I have an OpenGL window drawing behind a QtWebKit overlay. The OpenGL window has multiple "subwindows" that can be overlapping, which are decorated using the WebKit overlay. When they overlap though, because of this two layer system, the decorations for the overlapped windows do not get occluded.
The backup option is just to use a full-window canvas for this (the window trimmings are fairly simple), but it would be nicer not to. Note that because this is an embedded WebKit instance, it doesn't need to be cross-browser, and something WebKit (or QtWebKit) specific is fine.
EDIT
I can't answer my own question within 24 hours, so here's my solution, with thanks to #Kevin Peno
The following is a simplified version of what I was looking for. It creates two divs "visible" and "invisible". "invisible" masks off "visible" so that it displays the background image behind it instead of the "visible" div.
The real keys are -webkit-mask-image (http://www.webkit.org/blog/181/css-masks/) and -webkit-canvas (http://www.webkit.org/blog/176/css-canvas-drawing/), so this will only work with webkit-based browsers.
HTML:
<html>
<body>
<div id="visible"/>
<div id="invisible"/>
</body>
</html>
JavaScript:
function updateMask()
{
var w = $("#visible").width();
var h = $("#visible").height();
var context = document.getCSSCanvasContext("2d", "mask", w, h);
context.fillStyle = "rgba(255, 255, 255, 1.0)";
context.fillRect(0, 0, w, h);
var my_off = $("#visible").offset();
var inv_off = $("#invisible").offset();
var rel_left = inv_off.left - my_off.left;
var rel_top = inv_off.top - my_off.top;
context.clearRect(rel_left, rel_top, $("#invisible").width(), $("#invisible").height());
}
$(window).ready(function()
{
updateMask();
$("#invisible").draggable();
$("#invisible").bind("drag", function(e, ui)
{
console.log("drag");
updateMask();
e.preventDefault();
});
});
CSS:
body
{
background-image: url(http://www.google.com/images/logos/ps_logo2.png);
}
#visible
{
position: absolute;
background-color: red;
z-index: 0;
width: 1000px;
height: 1000px;
top: 0;
left: 0;
-webkit-mask-image: -webkit-canvas(mask);
}
#invisible
{
position: absolute;
z-index: 1;
width: 100px;
height: 100px;
top: 50px;
left: 50px;
cursor: move;
background-color: rgba(0, 255, 0, 0.5);
}
Here's a blog post about using css to apply an image mask to an element. It sounds pretty close to what you are looking for or will at least be good for some ideas. Let me know how it works out.
CSS Masks