var default_email;
$(document).ready(function(){
	$("#email").attr("value",default_email);
	$("#email").attr('class','g');
	$("#submit").attr("disabled", true);
	
	$("#email").change(function(){change(this);});
	$("#email").keyup(function(){change(this);});
	$("#email").focus(function(){focus(this);});
	$("#email").blur(function(){blur(this);});
});

function focus(obj){
	if(obj.value==eval('default_'+obj.id)){
		obj.value = '';
		obj.className = '';
	}
}
function blur(obj){
	if(obj.value==''){
		obj.value = eval('default_'+obj.id);
		obj.className = 'g';
	}
}
function change(obj){
	var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
	if(reg.test(obj.value) == true)
		$("#submit").removeAttr("disabled");
	else
		$("#submit").attr("disabled", true);
}