//-- Functions to validate user credentials --//
function validatePass(passwd, error) {
    if(passwd.value.length < 6) {
        alert(error);
        passwd.focus();
        passwd.select();
        return false;
    }
    if ( !( (passwd.value.search(/[a-zA-Z]+/) > -1) && (passwd.value.search(/[0-9]+/) > -1) && (passwd.value.search(/^[a-zA-Z0-9]+$/) > -1) ) ) {
        alert(error);
        passwd.focus();
        passwd.select();
        return false;
    }
    return true;
}

function validateEqual(field1, field2, error) {
    if(field1.value != field2.value) {
        alert(error);
        field1.focus();
        field1.select();
        return false;
    }
    return true;
}

function validateRequired(field, error) {
    if(field.value.length == 0) {
        alert(error);
        field.focus();
        field.select();
        return false;
    }
    return true;
}

function stdValidate(field, valid, error) {
    for (var i=0; i<field.value.length; i++) {
        if (valid.indexOf(field.value.substring(i, i+1)) == "-1") {
            alert(error);
            field.focus();
            field.select();
            return false;
        }
    }
    return true;
}

function validateEmail(field, error) {
    if((-1 == field.value.indexOf("@")) || (-1 != field.value.indexOf(",")) || (-1 != field.value.indexOf("#")) || (-1 != field.value.indexOf("!")) || (-1 != field.value.indexOf(" ")) || (field.value.length == (field.value.indexOf("@")+1))) { 
         field.focus(); 
         alert(error); 
         return false; 
    }
    return true;
}

/***  add something like this in the file you want to use it in *****
function validateFields() {
    if(!validateRequired(document.mainform.first, "You must enter a first name."))
        return false;
    if(!validateRequired(document.mainform.last, "You must enter a last name."))
        return false;
    if(!validateRequired(document.mainform.username, "You must enter a username."))
        return false;
    if(!stdValidate(document.mainform.username, "abcdefghijklmnopqrstuvwxyz0123456789",  "A username can contain only lowercase alphanumeric characters."))
        return false;
    if(!validateRequired(document.mainform.password1, "You must enter a password."))
        return false;
    if(!validatePass(document.mainform.password1, "Your password must be at least 6 characters long and contain alphanumeric characters."))
        return false;
    if(!validateEqual(document.mainform.password1, document.mainform.password2, "The passwords do not match."))
        return false;
    if(!validateEmail(document.mainform.email, "You must enter a valid email address"))
        return false;
    if(!validateRequired(document.mainform.email, "You must enter an email address"))
        return false;
    return true;
}
***/