function isEmpty(f, m) {
    if (f.val() == "") {
        f.focus();
        return m;
    } else {
        return "";
    }
}

function isMatch(s, f, m) {
    if (f.val() != s.val()) {
        s.focus();
        return m;
    } else {
        return "";
    }
}

function isEmailID(f, m) {
    var elementValue = f.val();
    var emailPattern = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/;
    if (emailPattern.test(elementValue)) {
        return "";
    } else {
        f.focus();
        return m;
    }
}

function isLength(f, n, m) {
    if (f.val().length < n) {
        f.focus();
        return m;
    } else {
        return "";
    }
}

function isMobile(f, m) {
    var elementValue = f.val();
    var mobPattern = /[7-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]/;
    if (mobPattern.test(elementValue)) {
        return "";
    } else {
        f.focus();
        return m;
    }
}

function isNumber(f, m) {
    var elementValue = f.val();
    var mobPattern = /[1-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]/;
    if (mobPattern.test(elementValue)) {
        return "";
    } else {
        f.focus();
        return m;
    }
}