Why do negative margins affect my page width? - html

Please reference the following example:
In it, an outer div 200px wide is meant to establish our page width. It contains an inner div 400px wide, but with left/right negative margins of -100px.
My intended end result is that the browser register total content width at 200px, not 400px, but horizontal scrollbars show up as soon as the window is resized to less than 400px. What is going on here?

Negative margins don't adjust the width of the div. A negative left margin will move the div to the left of it's position in the flow of the page, and a negative right margin will allow other elements to overlap the right hand side of the div by the amount of the margin.
You can hopefully see what I mean in this jsFiddle.
From your question it sounds like you need overflow: hidden to contain a large div within a smaller one without spilling out of its boundaries.

Gareth's answer is correct. Even with negative margin, the div is still part of the standard page flow and will not be ignored with respect to layout. Genuine page content cannot be ignored for scrolling purposes.
However, if you're doing this for an aesthetic, such as having a shadow down the sides of the page that extends beyond your max width, this can be achieved with a background - this question should help.

as Gareth already mentioned, margins do not affect the box size. The solution is rather simple. The outer container needs to be 400px, this is what is going to trigger the horizontal scroll bars. The inner container needs to be 200px with 100px left and right margins. When you resize the window, the scroll bars appear as soon as you have gotten smaller than the outer container.
http://jsfiddle.net/58VFB/

Try adding this to your CSS...
body {
overflow-y: scroll;
overflow: -moz-scrollbars-vertical;
}

Related

Fix div at the bottom of a *positioned fixed sidebar* only if there is enough vertical space available

I have a fixed sidebar and I want to stick a div to the bottom of it only if there is enough vertical space available.
If there is not enough vertical space the fixed div should not overlap the previous element, instead it should be on the flow and generate a scrollbar instead.
Any ideas?
You should look at the div that refers to your sidebar and apply a minimum height to it in your CSS.
#sidebardiv{
min-height: XXXXpx; <--- Where the number of pixels is at least the
} combined height and margins of all 3 boxes.

<div> with margin-left and right set to auto becomes uncentered >1634px

I have a div, .instagram_grid which has margin-left and margin-right set to auto, is relatively positioned, and has a width which for browse sizes 900px >makes the div be centered nicely in the page.
when I have the simple structure in the context of the rest of the CSS for a single page, the no longer becomes centered at browser width >1684px. In the Fiddle that follows I only have two lines that modify the div as a whole (and one just sets the background to pink). There are no media queries present, which suggests that it is the effect of some unseen preceding div/element causing the behavior.
https://jsfiddle.net/ebbnormal/m561tpnL/6/
The behaviour is what is expected with that markup.
The element is centered, but then you use relative positioning to show it 500px to the right of where it actually would be.
The .calc-text div above the .instagram_grid div causes its parent to overflow by setting margin-left:auto while simultaneously setting left: to a negative value, which isn't valid CSS.

How to make expandable div with min-height

If I have a div with height:100% & width:100%, it's background color will be up to the browser's height and width primarily. But if the content inside that div grows dynamically, then, the div will not expand according to the content, text will be overlapped and flows over that div.
On the other hand, if I set min-height and min-width to 100%, then if the content length is smaller than browser's window, background-color will not stretched to browser's height and width.
html, body{
height: 100%;
margin: 0;
padding: 0;
}
#container{
height: 100%;
width: 100%;
background-color: red;
}
How to make such div which background-color will cover up browser's window size primarily but if the content grows dynamically, it will be able to expand with content at the same time.
Regards.
I still don't know what you are actually trying to achieve. Going by your fiddle sample, it would have been much easier to just use a solid border around the inner diver to get a red surrounding (instead of another div with background color and padding). But if you just don't want that the text oveflows the div, you have to allow the div to resize:
http://jsfiddle.net/JQ7fr/1/
Update
I think see your problem now. What you are trying to do is not possible the way you are trying to do it. You are falling for a fundamental misconception of the CSS Box Model. The min-height of a box always refers to the height of its parent. If the height of the parent is not set, the height is auto by default, which means the height is calculated by the browser to be as big as necessary for the content of the box to fit. It is also calculated that way if you set a min-height!
Assume you give body a height of 100%, the body is as high as your browser window. If give your outer div a min-height of 100%, it will also be as high as your browser window, but since you set no height (setting min-height does NOT affect the height property!), the height of this box is auto. So in fact, the real height (CSS standard calls this the "tentative height") is only as big as the content of your outer div (not necessarily 100%), yet since min-height says it must be 100% it will render with a height of 100%, regardless what its real height is. If you now set min-height of your inner div to 100%, those 100% mean "100% of the height of my parent box height" and the parent box height is auto, it is NOT 100%! That's why the inner div does not fill the whole screen then.
Of course you can give your outer div a height of 100%, in that case setting the min-height of your inner div to 100% will make it fill the whole screen, but now the outer div is really just 100% in height, it will not expand beyond 100% (it has a FIXED HEIGHT), not even if the inner div is bigger than that, that's why red color will not expand beyond the screen height, even if the yellow color goes beyond the screen height.
Either your outer div has a fixed height, in which case the height will be fixed (that's the whole point of a fixed height, isn't it?) or it has a flexible height, but if it has a flexible height, it will never be "higher" than required for its content (the inner div) and thus using 100% at the inner div, whether you set min-height or height doesn't matter, always refers to 100% of the outer div height and that one will be as big as required for the inner div. I hope you were able to understand what I'm saying here.
You can surely get outer div to behave the way you want (always fill at least 100% of the screen, but expand beyond that if the content requires it) by just setting it's min-height to 100%, since here min-height will refer to the body height and your body has a fixed height, but the inner div will never behave that way. Well, it can behave that way, if your outer div has a fixed width, but then the outer div will not expand, not even if the inner div would require it, instead the inner div will overflow beyond the bounds of the outer one.
I'm pretty sure it is no problem to some create a web page that will look exactly the way you want it to look, but the problem is, we (or I) don't know what it is supposed to look. I doubt you want an ugly yellow page with a red and blue border around it, do you? Yet so far this is the only page we have seen from you. I don't know what kind of color effect you are trying to achieve, whether you are using images (or if you should be using images) or how the page will really look like in the end.
I can't understand your question very clearly, I think you should set a correct overflow property to your div,
try giving it overflow: auto; or any other suitable one
The CSS Overflow Property

Overflow-X in IE8

I have overflow-x:hidden placed on the body tag of my page so that any content extending beyond the window will not be visible. No scroll bars show up, however, I can still scroll to the left / right to see the content (kinda defeats the purpose of overflow-x).
-ms-overflow-x: doesn't fix the problem either.
There is a wrapper 900px;
Inside the wrapper, there is a div inside:
width:100%;
padding-right:300px;
position:absolute;
left:200px;
I would like the inner div to hang over the right side of the window without causing it to scroll (and leaving a 200px space the its left).
Any help? Thanks!
Since the width of the div is 100%, there should never be an overflow, since the div will always fit 100% of the viewport (assuming you haven't changed the size of your body tag).
As for the padding, the padding is added on after the width, so you're saying the div is 100% of the width of it's container (the body tag), and the padding is an additional 300px to the right, which will be invisible as it's out of the viewport.
You might want to try giving the div an explicit size width and experiment that way.
It may help to see an example of your markup as well, to get an idea of what you're trying to achieve.
More HTML/CSS would be useful, but given what you have right now, my first thought is that your wrapper is still set to position: static (the default for HTML elements).
If you add position: relative to your wrapper, it will contain the absolutely-positioned element within it, and should constrain it to the overflow restrictions.
Additionally, you may want to look into the box-sizing property and how the W3C box model works. In short, your padding is adding to the width of the element, so it's actually (100% + 300px), which results in a size that is larger than the container.
If you don't want to mess with box-sizing, you can also add max-width: 100% to your absolute div to force it to not grow out of its container.

Prevent HTML elements from overlapping each other on smaller screens

I have two elements on a page that are aligned side by side to each other. The element on the left is fixed. My default screen resolution is 1280x800. As the screen resolution decreases to 1024x* or less, the left and right containers tend to overlap each other. Is there a fix to this problem? How do I do it?
-----------------------------------------------------------Edit-----------------------------------------------------------
Actually, the element to the right is assigned a pre-defined width and is set to margin:0 auto to keep it oriented to the center of the screen. The element to the right left is a vertical menu, and hence, I want it to stay fixed even when the user scrolls the page. Hence I've specified position:fixed for it.
You could do this client side, shrinking the containers appropriately in a window.onresize event handler.
If they're colliding because the screen isn't big enough to hold both of them, try setting the width of the elements to a percentage: <tag style="width: 80%;" />.