I am trying to set the width 100% on text box but it stretches out the container.. I have checked some questions of the similar kind but there seems no explanation as to why the problem happens.. I know to manually set the properties but I need to find out why this happens. and I am must do it using the 100% property value..
<body>
<form id="form1" runat="server">
<div style="border:1px solid gray;">
<input type="text" style="width: 100%;" id="title"/>
</div>
<div>
<a href="#" id="postfile" style="float:left;">Post</a><span style="display:none; border:1px solid #ee1100; margin-left:10px; color:#cc1100" id="errormessage"></span>
</div>
</form>
Try using Box sizing on your input
Also the most cross browser way is :
http://jsfiddle.net/zQXXh/