$(document).ready(function(){
    // first capture the click and remove the text
    $('#login1').click(function(){
        if($(this).val()=='Username'){
            $(this).val('');
        }
    });


    // when the user clicks out of the field
    // check the contents and replace/act accordingly
    $('#login1').blur(function(){
        if($(this).val()==''){
            $(this).val('Username');
        }
    });    
});