Form Validation (JQuery) I made a simple form validation. It's working alright. The thing is I want my code to be optimized. Can somebody show me some pointers to improve my code? Thanks in advance.

$(document).ready(function(){

$('.submit').click(function(){
     validateForm();     
});


function validateForm(){
    var nameReg = /^[A-Za-z]+$/;
    var numberReg =  /^[0-9]+$/;
    var emailReg = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/;

    var names = $('#nameInput').val();
    var company = $('#companyInput').val();
    var email = $('#emailInput').val();
    var telephone = $('#telInput').val();
    var message = $('#messageInput').val();

    var inputVal = new Array(names, company, email, telephone, message);

    var inputMessage = ["name", "company", "email address", "telephone number", "message"];

    var textId = ["#nameLabel", "#companyLabel", "#emailLabel", "#telephoneLabel", "#messageInput"];

     $('.error').hide();

        if($.trim(inputVal[0]) === ""){
            $('#nameLabel').after('&lt;span class="error"&gt; Please enter your ' + inputMessage[0] + '&lt;/span&gt;');

        }else if(!nameReg.test(names)){
            $('#nameLabel').after('&lt;span class="error"&gt; Letters only&lt;/span&gt;');
        }

        if($.trim(inputVal[1]) === ""){
            $('#companyLabel').after('&lt;span class="error"&gt; Please enter your ' + inputMessage[1] + '&lt;/span&gt;');
        }

        if($.trim(inputVal[2]) === ""){
            $('#emailLabel').after('&lt;span class="error"&gt; Please enter your ' + inputMessage[2] + '&lt;/span&gt;');

        }else if(!emailReg.test(email)){
            $('#emailLabel').after('&lt;span class="error"&gt; Please enter a valid email address&lt;/span&gt;');
        }

        if($.trim(inputVal[3]) === ""){
            $('#telephoneLabel').after('&lt;span class="error"&gt; Please enter your ' + inputMessage[3] + '&lt;/span&gt;');

        }else if(!numberReg.test(telephone)){
            $('#telephoneLabel').after('&lt;span class="error"&gt; Numbers only&lt;/span&gt;');
        }

        if($.trim(inputVal[4]) === ""){
            $('#messageLabel').after('&lt;span class="error"&gt; Please enter your ' + inputMessage[4] + '&lt;/span&gt;');
        }   



    return false;

}   



});
First of all, you shouldn't use $('.submit').click() but $('#myForm').submit() as you will be able to submit forms by pressing enter too.
To check if a string is a number, use !isNan(string) (see this answer for more information).
Email regex are difficult things. Just check if there is someting before the @ (with .+?) and if there is something after the @ (again with .+?) and if that last part contains a . and a couple of characters (from 2 to 6)
It would make the function a lot easier if you put all specific code outside it. E.g:


    validateForm({
        '#nameInput': {
            'valid': function (value) {
                return /^[a-z]+$/i.test(value);
            },
            'label': '#nameLabel',
            'messages': {
                'empty': 'Please enter your name',
                'invalid': 'Letters only',
            },
        },
        '#companyInput': {
            'label': '#companyLabel',
            'messages': {
                'empty': 'Please enter your company',
            },
        },
        // ...
    });