A quick snippet to clear an inputs default value on focus and revert to the original value on blur:

$('input[type=text]').focus(function()
{
if($(this).val() == (this.defaultValue)) $(this).val('') }).blur(function()
{
if(!$(this).val()) $(this).val(this.defaultValue)
});

The selector assumes input[type=text] only. You may add input[type=password], textarea, etc.