Im guessing your are trying to use font-awesome.
They have a cheatsheet with unicodes here: http://fortawesome.github.io/Font-Awesome/cheatsheet/
This can be placed in the placeholder in html:
<input name="username" placeholder="">
Remember to add the on the input element:
font-family: 'FontAwesome'
This is not supported by all browsers so you might want to do a fallbackhack with the :before element.
.wrapper:before {
font-family: 'FontAwesome';
color:red;
position:relative;
content: "\f042";
}
Last fallback is to actually use an image like this:
background-image: url(http://www.levenmetwater.nl/static/global/images/icon-search.png);
background-position: 10px center;
background-repeat: no-repeat;
If you want it to remove the icon on focus, add this:
input:focus {
background-position: -20px center;
text-indent: 0;
width: 50%;
}