Is there a ('newbie-simple') way to embed an image inside html, however not in the inline form as usual:
<img src="data:image/png;base64,iVBORw0KGgoAAAA [...]" />
but in a form where the base64 code is placed on the end of the html file?
A possible benefit of this method would be that an image can be inserted in the page on more than one place using the same image data from the bottom of the html file.
TL;DR: With pure HTML/CSS - unfortunately no.
I need that too for Sciter Notes project to save notes (plain HTML files) with embedded images.
Ideally you should be able to do something like this:
<img src="cid:1234" />
...
<data id=1234 type="image/png" base64>
iVBORw0KGgoAAAA...
</data>
but unfortunately no such mechanism yet.
But you can implement schema explained above with script though.
If you are using HTML5, then you do not have to worry about caches. The browser will load all images and store them into an image-list, therefore the image will be loaded only once and reused at every place the key (the URL to the source image) is found.
The only thing you will have to do, if you are only using HTML, is to copy the URL of the image into every place you need to use it. This is necessary, because you cannot declare variables in HTML and hence cannot change them from another place in the document. For this purpose you would need additionally javascript for example.
Then you can go ahead with CSS to adjust the pictures to your requirements. Yu can either define classes in the header and let the img tags have these classes, or you can type the style properties inline or you can import an external CSS-file.
EDIT:
An example with javascript would be to add this code in
<body>
<img id="img" src="myIMG.jpg">
<script type="text/javascript">
function changeImage(id, src) {
document.getElementById(id).src=a;
}
</script>
</body>
Here the function changeImage is declared now. You can call this function either via onclick or inside of the script tag. You can address the correct image through its ID as first parameter (you will have to give every image its ID, don't confuse it with the image-list of your browser, here you define the ID in the img-tag) and the new source url as second parameter.
I am making help content documentation for an already made software (the kind of which opens in every software when you press F1 or navigate to the Help section in the menu bar). I am using simple html/CSS/js pages to do so.
There is a ton of the same text descriptions of various software properties that appear in more than one page. The idea is to make a single text source file, where all the text descriptions are located and then use some sort of referencing to that specific text section wherever necessary.
Kind of a similar to using a CSS stylesheet to apply styles over all of the pages, only this handles text instead of styles. This way I would be able to change text in only one file and it would apply everywhere it is used.
I ran across the html SSI method, but this only includes the entire html page and not just a specific text section the way I would like to. I would strongly avoid using different file for each text section.
Can anyone please point me into the right direction here?
I think that you can make a JavaScript function that contains the common texts and use this functions in your code whenever you need them, for this the JavaScript that you create should be an external file and you can reference it in every html page you need it.
For example, you can have one function that returns "Hello World" and set this to a "p" element with the id="title". So in every page where you have an element with the id title you can call your JavaScript function to set its text to "Hello World". Use this link to find out more about this topic:
http://www.w3schools.com/js/js_htmldom_html.asp
UPDATE: I did a little test, i created the following JavaScript:
function helloTitle(){
var text = "Hello World!";
document.getElementById("title").innerHTML = text;
}
And referenced it in some HTML pages like this:
<script src="commonText.js" type="text/javascript"></script>
After that i only need to call the function in the element i want it to modify:
<p id="title"><script>helloTitle();</script></p>
This is a solution if you are only using JS, CSS and HTML. There should be other ways to achieve this.
Hope this information could help you!
I figured out how to do it a little more comforatbly on a large scale using the html command https://www.w3schools.com/tags/tag_iframe.asp
in your main html file you do:
<p> <iframe src="Text.html" width="100%" height="300" style="border:1px solid black;"> </p>
and then with some basic html formating insert whatever text u want
<html>
<body>
hmm idk what i should put here. Test
</body>
</html>
there will also be some css formatting needing to be done before it look perfect, but if you want to make multi line blocks I think this is the easiest way to.
Let's say I have a CSS sheet that holds information for how a site that shows system statuses is presented. Depending on the status of the site, one of the following will be an attribute to the status:
#green_status
{
color: white;
text-align: left;
background: url(images/green.jpg) no-repeat;
}
#yellow_status
{
color: white;
text-align: left;
background: url(images/yellow.jpg) no-repeat;
}
#red_status
{
color: white;
text-align: left;
background: url(images/red.jpg) no-repeat;
}
and an XML document that stores details for individual sites and their statuses
<site>
<name>New Site</name>
<headerImage>header image goes here</headerImage>
<systemStatus color="green">Normal</systemStatus>
<networkNotes>System status is normal</networkNotes>
</site>
I am going to use XML DOM to select values from the XML to populate elements of the page. Though after some testing I am still finding that I can change the text of the system's status but not the bar color without actually changing the site's attributes.
I'd like to be able to just change the XML file and set <systemStatus color"red">SYSTEM IS DOWN</systemStatus> and have that change not only the text, but the bar color to "red.jpg" without having to go in to the html and manually edit the status.
So far in order to solve this, I've added the 'color="green, yellow, red"' attribute to my XML elements, added 2 new statuses to the CSS (indicated by the first code block of this question), and have so far been unable to connect the dots.
Is there a way that I can make it to where the changes only need to be made to the XML file to change both the text & bar color for the system status of that site? The end goal here is to be able to just change the XML attribute and text of the systemStatus and change both the bar & the text on the site.
Use the CSS3 attribute selector.
<systemStatus color="green">
CSS:
systemStatus[color='green'] {
background-color:#2f2;
}
You can link a CSS stylesheet to an XML file using this processing instruction:
<?xml-stylesheet href="my-style.css"?>
... rest of document here...
More details about it can be found here: http://www.w3.org/Style/styling-XML
With that, you can add styling to any element and even use attributes in the selector:
systemStatus[color="red"] {
color: red;
}
I think you can also use special selectors like :first-child and such.
Afaik, there is no way to include Javascript in an XML file, but you should be able to tranform the XML into another XML if the current XML doesn't have the structure you need.
In the transformation you can add the elements and properties you need to be able to style it. See also Xml to Xml transformation using XSLT.
What everybody else said, plus you can set the content via CSS too:
systemStatus[color='green']::after {
content: "ALL IS WELL";
}
I suggest using a descriptive term for the attribute rather than explicitly a color, so that you can change your mind later about what the display should be without changing the nomenclature. Something like
<systemStatus status="ok"/>
and in CSS
systemStatus[status="ok"] {
color: green;
background-color: white;
}
XML does not specify any display or formatting, so if you really want to show a text as green, you need to do that using the display language (e.g. HTML or XSL-FO).
You can specify a tag to contain (X)HTML fragment, either as XHTML fragment, e.g.
<site xmlns:h="http://www.w3.org/1999/xhtml">
...
<systemStatus><h:p class="ok" style="color: green;">Normal</h:p></systemStatus>
...
</site>
or as CDATA:
<site>
...
<systemStatus><![CDATA[<p class="ok" style="color: green;">Normal</p>]]></systemStatus>
...
</site>
Your host display language (HTML+Javascript in your case) has to then insert this into the host document's DOM as an (X)HTML fragments or textually with element.innerHTML.
Be careful about inserting with innerHTML from untrusted source though, if the data in the XML file comes untrusted source, they may potentially contain Javascript code, which may then be executed when inserted into the host HTML.
I’m working on a CSS file that is quite long. I know that the client could ask for changes to the color scheme, and was wondering: is it possible to assign colors to variables, so that I can just change a variable to have the new color applied to all elements that use it?
Please note that I can’t use PHP to dynamically change the CSS file.
CSS supports this natively with CSS Variables.
Example CSS file
:root {
--main-color:#06c;
}
#foo {
color: var(--main-color);
}
For a working example, please see this JSFiddle (the example shows one of the CSS selectors in the fiddle has the color hard coded to blue, the other CSS selector uses CSS variables, both original and current syntax, to set the color to blue).
Manipulating a CSS variable in JavaScript/client side
document.body.style.setProperty('--main-color',"#6c0")
Support is in all the modern browsers
Firefox 31+, Chrome 49+, Safari 9.1+, Microsoft Edge 15+ and Opera 36+ ship with native support for CSS variables.
People keep upvoting my answer, but it's a terrible solution compared to the joy of sass or less, particularly given the number of easy to use gui's for both these days. If you have any sense ignore everything I suggest below.
You could put a comment in the css before each colour in order to serve as a sort of variable, which you can change the value of using find/replace, so...
At the top of the css file
/********************* Colour reference chart****************
*************************** comment ********* colour ********
box background colour bbg #567890
box border colour bb #abcdef
box text colour bt #123456
*/
Later in the CSS file
.contentBox {background: /*bbg*/#567890; border: 2px solid /*bb*/#abcdef; color:/*bt*/#123456}
Then to, for example, change the colour scheme for the box text you do a find/replace on
/*bt*/#123456
Yeeeaaahhh.... you can now use var() function in CSS.....
The good news is you can change it using JavaScript access, which will change globally as well...
But how to declare them...
It's quite simple:
For example, you wanna assign a #ff0000 to a var(), just simply assign it in :root, also pay attention to --:
:root {
--red: #ff0000;
}
html, body {
background-color: var(--red);
}
The good things are the browser support is not bad, also don't need to be compiled to be used in the browser like LESS or SASS...
Also, here is a simple JavaScript script, which changes the red value to blue:
const rootEl = document.querySelector(':root');
root.style.setProperty('--red', 'blue');
CSS itself doesn't use variables. However, you can use another language like SASS to define your styling using variables, and automatically produce CSS files, which you can then put up on the web. Note that you would have to re-run the generator every time you made a change to your CSS, but that isn't so hard.
You can try CSS3 variables:
body {
--fontColor: red;
color: var(--fontColor);
}
There's no easy CSS only solution. You could do this:
Find all instances of background-color and color in your CSS file and create a class name for each unique color.
.top-header { color: #fff; }
.content-text { color: #f00; }
.bg-leftnav { background-color: #fff; }
.bg-column { background-color: #f00; }
Next go through every single page on your site where color was involved and add the appropriate classes for both color and background color.
Last, remove any references of colors in your CSS other than your newly created color classes.
The 'Less' Ruby Gem for CSS looks awesome.
http://lesscss.org/
Yes, in near future (i write this in june 2012) you can define native css variables, without using less/sass etc ! The Webkit engine just implemented first css variable rules, so cutting edge versions of Chrome and Safari are already to work with them. See the Official Webkit (Chrome/Safari) development log with a onsite css browser demo.
Hopefully we can expect widespread browser support of native css variables in the next few months.
Do not use css3 variables due to support.
I would do the following if you want a pure css solution.
Use color classes with semenatic names.
.bg-primary { background: #880000; }
.bg-secondary { background: #008800; }
.bg-accent { background: #F5F5F5; }
Separate the structure from the skin (OOCSS)
/* Instead of */
h1 {
font-size: 2rem;
line-height: 1.5rem;
color: #8000;
}
/* use this */
h1 {
font-size: 2rem;
line-height: 1.5rem;
}
.bg-primary {
background: #880000;
}
/* This will allow you to reuse colors in your design */
Put these inside a separate css file to change as needed.
Sure can, sort of, thanks to the wonderful world of multiple classes, can do this:
.red {color:red}
.blackBack {background-color: black}
but I often end up combining them anyway like this:
.highlight {color:red, background-color: black}
I know the semantic police will be all over you, but it works.
I'm not clear on why you can't use PHP. You could then simply add and use variables as you wish, save the file as a PHP file and link to that .php file as the style sheet instead of the .css file.
It doesn't have to be PHP, but you get what I mean.
When we want programming stuff, why not use a programming language until CSS (maybe) supports things like variables?
Also, check out Nicole Sullivan's Object-oriented CSS.
You can group selectors:
#selector1, #selector2, #selector3 { color: black; }
You could pass the CSS through javascript and replace all instances of COLOUR1 with a certain color (basically regex it) and provide a backup stylesheet incase the end user has JS turned off
dicejs.com (formally cssobjs) is a client-side version of SASS. You can set variables in your CSS (stored in json formatted CSS) and re-use your color variables.
//create the CSS JSON object with variables and styles
var myCSSObjs = {
cssVariables : {
primaryColor:'#FF0000',
padSmall:'5px',
padLarge:'$expr($padSmall * 2)'
}
'body' : {padding:'$padLarge'},
'h1' : {margin:'0', padding:'0 0 $padSmall 0'},
'.pretty' : {padding:'$padSmall', margin:'$padSmall', color:'$primaryColor'}
};
//give your css objects a name and inject them
$.cssObjs('myStyles',myCSSObjs).injectStyles();
And here is a link to a complete downloadable demo which is a little more helpful then their documentation : dicejs demo
EDIT: This answer is no longer current. You should use CSS variables now.
Consider using SCSS. It's full compatible with CSS syntax, so a valid CSS file is also a valid SCSS file. This makes migration easy, just change the suffix. It has numerous enhancements, the most useful being variables and nested selectors.
You need to run it through a pre-processor to convert it to CSS before shipping it to the client.
I've been a hardcore CSS developer for many years now, but since forcing myself to do a project in SCSS, I now won't use anything else.
If you have Ruby on your system you can do this:
http://unixgods.org/~tilo/Ruby/Using_Variables_in_CSS_Files_with_Ruby_on_Rails.html
This was made for Rails, but see below for how to modify it to run it stand alone.
You could use this method independently from Rails, by writing a small Ruby wrapper script
which works in conjunction with site_settings.rb and takes your CSS-paths into account, and
which you can call every time you want to re-generate your CSS (e.g. during site startup)
You can run Ruby on pretty much any operating system, so this should be fairly platform independent.
e.g. wrapper: generate_CSS.rb (run this script whenever you need to generate your CSS)
#/usr/bin/ruby # preferably Ruby 1.9.2 or higher
require './site_settings.rb' # assuming your site_settings file is on the same level
CSS_IN_PATH = File.join( PATH-TO-YOUR-PROJECT, 'css-input-files')
CSS_OUT_PATH = File.join( PATH-TO-YOUR-PROJECT, 'static' , 'stylesheets' )
Site.generate_CSS_files( CSS_IN_PATH , CSS_OUT_PATH )
the generate_CSS_files method in site_settings.rb then needs to be modified like this:
module Site
# ... see above link for complete contents
# Module Method which generates an OUTPUT CSS file *.css for each INPUT CSS file *.css.in we find in our CSS directory
# replacing any mention of Color Constants , e.g. #SomeColor# , with the corresponding color code defined in Site::Color
#
# We will only generate CSS files if they are deleted or the input file is newer / modified
#
def self.generate_CSS_files(input_path = File.join( Rails.root.to_s , 'public' ,'stylesheets') ,
output_path = File.join( Rails.root.to_s , 'public' ,'stylesheets'))
# assuming all your CSS files live under "./public/stylesheets"
Dir.glob( File.join( input_path, '*.css.in') ).each do |filename_in|
filename_out = File.join( output_path , File.basename( filename_in.sub(/.in$/, '') ))
# if the output CSS file doesn't exist, or the the input CSS file is newer than the output CSS file:
if (! File.exists?(filename_out)) || (File.stat( filename_in ).mtime > File.stat( filename_out ).mtime)
# in this case, we'll need to create the output CSS file fresh:
puts " processing #{filename_in}\n --> generating #{filename_out}"
out_file = File.open( filename_out, 'w' )
File.open( filename_in , 'r' ).each do |line|
if line =~ /^\s*\/\*/ || line =~ /^\s+$/ # ignore empty lines, and lines starting with a comment
out_file.print(line)
next
end
while line =~ /#(\w+)#/ do # substitute all the constants in each line
line.sub!( /#\w+#/ , Site::Color.const_get( $1 ) ) # with the color the constant defines
end
out_file.print(line)
end
out_file.close
end # if ..
end
end # def self.generate_CSS_files
end # module Site
Not PHP I'm afraid, but Zope and Plone use something similar to SASS called DTML to achieve this. It's incredibly useful in CMS's.
Upfront Systems has a good example of its use in Plone.
If you write the css file as an xsl template, you could read color values from a simple xml file. Then create the css with an xslt processor.
colors.xml:
<?xml version="1.0"?>
<colors>
<background>#ccc</background>
</colors>
styles.xsl:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text" version="1.0" encoding="iso-8859-1"/>
<xsl:template match="/">body {
background-color: <xsl:value-of select="/colors/background" />;
}
</xsl:template>
</xsl:stylesheet>
Command to render css: xsltproc -o styles.css styles.xsl colors.xml
styles.css:
body {
background-color: #ccc;
}
It’s not possible with CSS alone.
You can do it with JavaScript and LESS using less.js, which will render LESS variables into CSS live, but it’s for development only and adds too much overhead for real-life use.
The closest you can come with CSS is to use an attribute substring selector like this:
[id*="colvar-"] {
color: #f0c69b;
}
and set the ids of all your elements that you want to be adjusted to names starting with colvar-, such as colvar-header. Then when you change the color, all the ID styles are updated. That’s as close as you can get with CSS alone.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
jQuery/Javascript to replace broken images
This should be easy I just don't know the terminology to be googling for. I think this is HTML/CSS, if an image link is broken it often shows a missing image icon showing a page with red, green, blue shapes. In HTML is it possible to configure "use this image if an image link is broken?"
An 'onerror' example:
<img src="fail.jpg" onerror="this.src='https://www.google.com.br/logos/2012/montessori-res.png';">
http://jsfiddle.net/u4hQd/
I think the heart of this is how to add dynamic functionality to CSS. I don't know of an if/else check in CSS apart from detecting browsers, however, this is what I would do if I ever need to do something like this.
If you are using php you can do this:
$imagename = "image.png";
if (file_exists($imagename)){
echo '<p class="exists">';
} else {
echo '<p class="dne">';
}
Then in the css you can have
.exists{background:url("../img/git-sprite.png") no-repeat 0px -32px;}
.dne{background:url("../img/git-sprite2.png") no-repeat 0px -32px;}
This way you can add an if/else functionality for this in the CSS itself. You don't have to use PHP, I'm sure a javascript would work as well
Your question is understandable without any additional terminology.
Unfortunately there are no means in HTML for what you want.
What you can do is use JS (jQuery will help), to cycle through all img tags in your document, and check which of them have images (check against null). For those, who miss their images, you can load some other image (some default).
But remember to run this script after the page has completely loaded (with all assets: JS, CSS, images), because if you run it before page loading is done, you may mistakenly put default image to some img tag, which had no time to load it's real image.
Are you using php?
You could check before sending the file with something like this:
$filename = "whatever.png";
if (file_exists($filename)){
$html = "<img src=\"$filename\">";
} else {
$html = "<img src=\"someotherpath.jpg\">";
}
echo $html;