function validateForm() {
    var errors='';
    
    if (document.formSignUp.koo_sign_email.value == '')
        errors += ':: Please enter an Email address.\n';
    
    if (errors == '')
    {
        var emailPat="^[a-zA-Z0-9]{1}[\.a-zA-Z0-9_-]*[a-zA-Z0-9]{1}@[a-zA-Z0-9]+[-]{0,1}[a-zA-Z0-9]+[\.]{1}[a-zA-Z]+[\.]{0,1}[a-zA-Z]+$";
        var matchArray=document.formSignUp.koo_sign_email.value.match(emailPat);
        if (matchArray == null) {
            errors += ':: Email address seemed not valid.\n';
        }
    }
    
    if (document.formSignUp.koo_sign_password.value == '')
        errors += ':: Please enter a password.\n';
    else
        if (document.formSignUp.koo_sign_password.value.length < 6)
            errors += ':: Password is too short, at least 6 letters long.\n';
    
    if (errors)
        alert('There are errors during the processing of sign up:\n\n'+errors);
    
    document.validReturnValue = (errors == '');

}