Q:

Strange GET Data Causing 404 Error - JavaScript Form Validation

I want to refer to this post, because it might relate:
Make Form Fields Optional with JavaScript Validation
I have a form with three optional fields, as described above.  If I click the submit button, the JavaScript alerts come up, but the last one is a URL instead of the string I specify in the JavaScript function (the one that isn't an alert strong but an URL).
After a second, the page tries to go to an invalid URL:
localhost.../index.php/Don%27t%20forget%20the%20location.
As it turns out the Don%27t%20forget%20the%20location. is the alert string I have in the JavaScript function.
I thought that I might have some weird code that I accidentally pasted somewhere causing this but I scoured my files and found nothing out of the ordinary that would cause this.  Not sure if this is a bug or something I'm doing wrong.
EDIT
I have JavaScript form validation functions like so:
function validate_name(field) 
{
    if (field == "") return "Please enter the name.\n";
    return "";
}

function validate_specialty(field) 
{
    if (field == "") return "Please enter the specialty.\n";
    return "";
}

function validate_location(field) 
{
    if (field == "") return "Don't forget the location.\n";
    return "";
}

where the function that is called from the form's onSubmit is:
function validate_form(form)
{
    name  = validate_name(form.name.value);
    specialty = validate_specialty(form.specialty.value);
    location = validate_location(form.location.value);

    if (name == "" || specialty == "" || location == "")
    {
        return true;
    }

    else 
    { 
        alert("You must enter at least one field:\n\n" + name + specialty + location);
        return false;
    }
}

A:

It's because the variable location refers to window.location in that case (the url). So if you change your variable name, that should work:
userLocation = validate_location(form.location.value);

and 
alert("You must enter at least one field:\n\n" + name + specialty + userLocation);

