// JavaScript Document
<!--邮箱验证-->
function CheckExists()
    {
       var e = document.getElementById("email").value;
        if(e=="")
			{
				alert("请输入格式正确的E-mail地址！");
				 return false;
			}
		if(e != "") {
          if(!/(\S)+[@]{1}(\S)+[.]{1}(\w)+/.test(e)) 
          {
             alert("请输入格式正确的E-mail地址！");
             //var email = document.getElementById ( "email" );
             //email.value = "";
             //email.focus ();
			 return false;
          } 
          else 
           {
              QuickRegisterBox.IsEMailExists(e, CheckExists_Callback);
           }
      }
  } 
  <!-- 鼠标放入文本框文字消失，离开文字出现 "focucmsg"-->
$(document).ready(function(){
$("TEXTAREA,input[focucmsg]") .each (function(){
$(this).val($(this).attr("focucmsg"));
$(this).val($(this).attr("focucmsg")).css("color","#979393");
$(this).focus(function(){
if($(this).val() == $(this).attr("focucmsg"))
{
$(this).val('');
$(this).val('').css("color","#6b6969");
}
});
$(this).blur(function(){
if(!$(this).val()){
$(this).val($(this).attr("focucmsg"));
$(this).val($(this).attr("focucmsg")).css("color","#979393");
}
});
});
});