First let me go over my original approach which was using <input type="image" src="image-path"> as follows:

<form method="get" id="searchform" action="http://www.sohtanaka.com/">
 <fieldset>
 <input type="text" value="" name="s" id="s" />
 <input type="image" src="http://stblog.tanaka.netdna-cdn.com/wp-content/themes/st2008/images/btn_search2.gif" id="searchsubmit" value="Search" class="btn" />
 </fieldset>
</form>

This was all fine and dandy but there was one annoying issue. The image button would not align with the search input box and I would have to add a negative top margin to correct this issue.

Revised Approach

With this revised approach, I decided not to go with the type="image" and used the <button> tag, and added a background with CSS. This allowed both input text box and the button to naturally align. I also added a :focus pseudo class for the final touch (IE will not read this, so I added a conditional style specifically for IE to hide this effect). Below are some benefits of this method:

• Aligns naturally
• Only uses one image for buttons and input box
• :focus pseudo class for browsers that support it
• Added hover effect for button

HTML

<form method="get" id="searchform" action="#">
<fieldset class="search">
 <input type="text" class="box" />
 <button class="btn" title="Submit Search">Search</button>
</fieldset>
</form>

CSS

fieldset.search {
 border: none;
 width: 243px;
 margin: 0 auto;
 background: #222;
}
.search input, .search button {
 border: none;
 float: left;
}
.search input.box {
 color: #fff;
 font-size: 1.2em;
 width: 190px;
 height: 30px;
 padding: 8px 5px 0;
 background: #616161 url(search_bg.gif) no-repeat;
 margin-right: 5px;
}
.search input.box:focus {
 background: #616161 url(search_bg.gif) no-repeat left -38px;
 outline: none;
}
.search button.btn {
 width: 38px;
 height: 38px;
 cursor: pointer;
 text-indent: -9999px;
 background: #fbc900 url(search_bg.gif) no-repeat top right;
}
.search button.btn:hover {
 background: #fbc900 url(search_bg.gif) no-repeat bottom right;
}

Conditional Comments for IE

<!--[if lte IE 7]>
<link rel="stylesheet" type="text/css" href="ie.css" />
<![endif]-->

IE Style Sheet – ie.css
**EDIT** Ingo Chao commented that IE6+7 scrolls the background-image horizontally if the input gets more content, so my fix was to use a unique background image strictly for IE, and instead of aligning to the left, I reversed it and aligned it to the right to correct this bug.

.search input.box {
 background: url(search_bg_ie.gif) no-repeat right bottom; /* Unique Input Box background image specifically for IE, and the background position must be aligned to the right*/
}