function $(id) {
    return document.getElementById(id);
}
function skyJSLogin() {
    var s;
    s = $("txtUserID");
    if (s.value == "") {
        alert("系统提示您，用户编号必须填写！");
        s.focus();
        return false;
    }
    s = $("txtUserPwd");
    if (s.value == "") {
        alert("系统提示您，用户密码必须填写！");
        s.focus();
        return false;
    }
	s = $("txtCheck");
	if (s.value == "") {
        alert("系统提示您，验证码必须填写！");
        s.focus();
        return false;
    }
	return true;
}
function skyJSLoginMain()
{
     var s;
    s = $("txtUserID");
    if (s.value == "") {
        alert("系统提示您，用户编号必须填写！");
        s.focus();
        return false;
    }
    s = $("txtUserPwd");
    if (s.value == "") {
        alert("系统提示您，用户密码必须填写！");
        s.focus();
        return false;
    }
	return true;
}

function nchangeImg()
{
   var img = document.getElementById("imgVerify");
   img.src = "/admin/skyRandomImages.aspx?" + Math.random();
   // var ctrl = document.getElementById("verifycode");
   // if (ctrl != null) {	ctrl.focus(); ctrl.select(); }
}