Is there a more efficient/optimized way to write this piece of jQuery?
<p>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?</p>

<pre><code>$("#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;
     }

    });
</code></pre>
