Replace text in input
HTML
<input type="text" id="mybox" name="phrase" value="Enter text here..." size="24"/>
JavaScript
var defaultValue = "Enter text here...",
newValue = "New text here...";
$('#mybox').focusin(function() {
$(this).val(newValue);
});
$('#mybox').focusout(function() {
$(this).val(defaultValue);
});