var lastnick = "";
function checkuser()
{
    var nick = document.regform.elements['username'].value;
    if (nick == "")
	{
		document.all("usefulMsg").innerText = "请先输入用户名";
        return false;
    }else if (nick.indexOf(String.fromCharCode(32)) != -1 || nick.indexOf(String.fromCharCode(34)) != -1 || nick.indexOf(String.fromCharCode(38)) != -1 || nick.indexOf(String.fromCharCode(39)) != -1 || nick.indexOf(String.fromCharCode(44)) != -1 || nick.indexOf(String.fromCharCode(47)) != -1 || nick.indexOf(String.fromCharCode(59)) != -1 || nick.indexOf(String.fromCharCode(60)) != -1 || nick.indexOf(String.fromCharCode(62)) != -1 || nick.indexOf(String.fromCharCode(92)) != -1 || nick.indexOf(String.fromCharCode(124)) != -1 || nick.indexOf('　') != -1)
    {
		document.all("usefulMsg").innerText = "用户名不能有空格及特殊字符";
        return false;
    }

	if (nick == lastnick)
	{
        return false;
    }

    lastnick = nick;
	checkform.checkuserform.checkname.value = nick;
	document.all("usefulMsg").innerText = "检测中，请稍等...";
	checkform.checkuserform.submit();
	return true;
}