为什么我在asp.net下面的javascript代码不起作用？

Question

<script language="javascript" type="text/javascript">
function validate() {
    summary += isvalidFirstName();
    summary += isvalidMobile();
    summary += checkPassword();
    summary += checkEmail();
    if (summary != "") {
        alert(summary);
        return false;
    } else
        return true;
}

function isvalidFirstName() {
    var uid;
    var temp = document.getElementById("<%=txtFirstName.ClientID %>");
    uid = temp.value;
    if (uid == "") {
        return ("Please enter firstname" + "\n");
    } else
        return "";
}

function isvalidMobile() {
    var mob = /^[1-9]{1}[0-9]{9}$/;
    var txtMob = document.getElementById(txtMobile);
    if (mob.test(txtMob.value) == false) {
        alert("Please enter valid mobile number");
        txtMob.focus();
        return false;
    } else
        return true;
}

function checkPassword(inputtxt) {
    var pass = /^[A-Za-z]\w{7,14}$/;
    if (inputtxt.value.match(pass)) {
        alert("Password is correct");
        return true;
    } else {
        alert("Wrong...!");
        return false;
    }
}

function checkEmail(inputtxt) {
    var mail = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
    if (inputtxt.value.match(mail)) {
        return true;
    } else {
        alert("Please enetr a valid email id");
        return false;
    }
}
</script>

我在.ASPX页面中添加了上面的javascript代码，并在按钮单击时调用了函数validate，但它无效。任何人都可以帮助我吗？