$(document).ready(function () {
		$('#user_email').bind('focus', function() 
			{ 
				if (this.value == "Adresse email")
					this.value = ''; 
			}
		);
		
		$('#user_email').bind('blur', function() 
			{ 
				if (this.value == '')
					this.value = "Adresse email";
			}
		);
	});