Quick JQuery plugin i wrote to clear textboxes when mouse is focused on them. And restore previous value on blur.

jQuery.fn.defValue = function(){
    return this.each(function(){
        $(this).focus(function(){
            var defVal = this.defaultValue;
            if($(this).val() == defVal){
                $(this).val('');/* Clear box if it hasnt changed */
            }
        }).blur(function(){
            var defVal = this.defaultValue;
            if($(this).val() == ''){
                $(this).val(defVal);
            }
        });
    });
}
//usage
$(document).ready(function(){
  $('input').defValue();
});

NOTE: This will work on text boxes only not Text area. With some tweeking it can work on text area. I’m just too lazy :) sorry…This is the part where you say challenge accepted!