if(b.email.value.length!=0)
{
var c=b.email.value;
if(c.charAt(0)=="."||c.charAt(0)=="@"||c.indexOf(".",0)==-1||c.indexOf("@",0)==-1||c.lastIndexOf("@")==c.length-1
||c.lastIndexOf(".")==c.length-1)
{
alert("Email的格式不对!");
b.email.focus();
return false;
}
}else
{
alert("Email 不能为空");
b.email.focus();
return false;
}