How to stretch the width of an element, so that it is (100% - widths of its siblings)?

http://stackoverflow.com/questions/3682649/how-to-stretch-the-width-of-an-element-so-that-it-is-100-widths-of-its-sibl

by Wexcode

HTML

<ul>
    <li>
        <input class="btn" type="button" value="Submit"/>
        <div class="inputbox"><input id="textField" type="text" /></div>
    </li>
</ul>

CSS

ul { 
  list-style: none; 
  padding: 0; }
.btn { float: right; }
.inputbox { 
  padding: 0 5px 0 0;
  overflow: hidden; }
.inputbox input { 
  width: 100%;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box; }