Question

What is the most efficient way of coding the below functions which warn people if they try to submit an empty form and also clear forms for them to enter?

$("#newsletter-subscribe").focus( function() { 
        if(this.value=='Your email address'){
            this.value='';
        }
    });

    $("#newsletter-subscribe").blur( function(){
        if(this.value==''){
            this.value='Your email address'
        }; 
    });

    $("#subscribe").bind("submit", function(e){
        email = $("input#newsletter-subscribe").val();
     $("input#newsletter-subscribe").val(email);
     if(jQuery.trim(email) == 'Your email address' || jQuery.trim(email) == '') {
      alert('Please enter your email address to subscribe.');
      return false;
     }

    });

Answer 1

You may want to look at the jQuery Watermark plugin.

This plugins let’s you add default text on form elements that look like watermarks or work as placeholders … work in a way to prevent unwanted information to be sent to the server