validate js

//--Validation
function validatePositiveDecimalsOnly(e) {
    if (e.keyCode != 46 && e.keyCode > 31
      && (e.keyCode < 48 || e.keyCode > 57))
        return false;
}

function validateNumbersOnly(e) {
    if ((e.keyCode < 48) || (e.keyCode > 57)) {
        return false;
    }
}

function validatePhoneNumber(e) {
    if ((e.keyCode < 48) || (e.keyCode > 57)) {
        if ((e.keyCode != 40) && (e.keyCode != 41) && (e.keyCode != 45))
            return false;
    }
}

function validateEmail(email) {
    var emailFormat = email.slice(email.indexOf('@'), email.length);
    if (email.indexOf('@') == -1 || emailFormat.indexOf('.') == -1) {
        if (email.length !== 0) {
            return false;
        }
        else {
            return true;
        }
    }
    else {
        return true;
    }
}

function isNumeric(val) {
    var numeric = true;
    var chars = "0123456789";
    var len = val.length;
    var char = "";
    for (i = 0; i < len; i++) {
        char = val.charAt(i);
        if (chars.indexOf(char) == -1) {
            numeric = false;
        }
    }
    return numeric;
}