function login() {
    if ($('username').value == '') {
	    $('msg').innerHTML = '<font color=red>请填写用户名</font>';
		return false;
	}
	if ($('passwd').value == '') {
		$('msg').innerHTML = '<font color=red>请填写密码</font>';
		return false;
	}
    if ($('checknum').value == '') {
		$('msg').innerHTML = '<font color=red>请填写验证码</font>';
		return false;
	}
	var pars = "cmd=login&username="+$('username').value+"&passwd="+$('passwd').value+"&checknum="+$('checknum').value+"&"+Math.random();
	disabled('login_btn',true);
    $('msg').innerHTML = '<font color=red>请稍候。。。</font>';
	var a=new Ajax.Request(
    	"operation/user.php",
    		 {method: 'post', parameters: pars, onSuccess: function(xmlRequest) {
	         var ret = trim(xmlRequest.responseText);
			 if (ret == '1') {
			     location.href='/user/index.php';
			 }else{
				 $('msg').innerHTML = '<font color=red>'+ret+'</font>';
				 checkimg();
			     //location.href='/login.php';
			 }
			 disabled('login_btn',false);
		}}
	);
}

function checkimg() {
    $('checkimg').src="http://union.kxting.com/checknumber.php?"+Math.random();
}