How can I do width = 100% - 100px in CSS?

Question

In CSS, how can I do something like this:

width: 100% - 100px;

I guess this is fairly simple but it is a bit hard to find examples showing

Answer 1

Working with bootstrap panels, I was seeking how to place "delete" link in header panel, which would not be obscured by long neighbour element. And here is the solution:

html:

<div class="with-right-link">
    <a class="left-link" href="#">Long link header Long link header</a>
    <a class="right-link" href="#">Delete</a>
</div>

css:

.with-right-link { position: relative; width: 275px; }
a.left-link { display: inline-block; margin-right: 100px; }
a.right-link { position: absolute; top: 0; right: 0; }

Of course you can modify "top" and "right" values, according to your indentations. Source

Answer 2

It started to work for me only when I checked all the spaces. So, it didn't work like this: width: calc(100%- 20px) or calc(100%-20px) and perfectly worked with width: calc(100% - 20px).

Answer 3

Are you using standards mode? This solution depends on it I think.

If you're trying to make 2 columns you could do something like this:

<div id="outer">
    <div id="left">
        sidebar
    </div>
    <div id="main">
        lorem ispsum etc... 
    </div>
</div>

Then use CSS to style it:

div#outer
{
    width:100%;
    height: 500px;
}

div#left
{
    width: 100px;
    height: 100%;
    float:left;
    background: green;
}

div#main
{
   width: auto;
   margin-left: 100px; /* same as div#left width */
   height: 100%;
   background:red;
}

If you don't want 2 columns you can probably remove <div id="left">

Answer 4

This works:

margin-right:100px;
width:auto;

Answer 5

You can look into using LESS, which is a JavaScript file that pre-processes your CSS so you can include logic and variables into your CSS. So for your example, in LESS you would write width: 100% - 100px; to achieve exactly what you wanted :)

Answer 6

my code, and it works for IE6:

<style>
#container {margin:0 auto; width:100%;}
#header { height:100px; background:#9c6; margin-bottom:5px;}
#mainContent { height:500px; margin-bottom:5px;}
#sidebar { float:left; width:100px; height:500px; background:#cf9;}
#content { margin-left:100px; height:500px; background:#ffa;}

</style>

<div id="container">
  <div id="header">header</div>
  <div id="mainContent">
    <div id="sidebar">left</div>
    <div id="content">right 100% - 100px</div>
  <span style="display:none"></span></div>
</div>