Error: Uncaught SyntaxError: Unexpected token <

This is a browser issue rather than a javascript or JQuery issue; it's attempting to interpret the angle bracket as an HTML tag.

Try doing this when setting up your javascripts:

<script>
//<![CDATA[

    // insert teh codez

//]]>
</script>

Alternatively, move your javascript to a separate file.

Edit: Ahh.. with that link I've tracked it down. What I said was the issue wasn't the issue at all. this is the issue, stripped from the website:

<script type="text/javascript"
    $(document).ready(function() {
    $('#infobutton').click(function() {
        $('#music_descrip').dialog('open');
    });
        $('#music_descrip').dialog({
            title: '<img src="/images/text/text_mario_planet_jukebox.png" id="text_mario_planet_jukebox"/>',
            autoOpen: false,
            height: 375,
            width: 500,
            modal: true,
            resizable: false,
            buttons: {
                'Without Music': function() {
                    $(this).dialog('close');
                    $.cookie('autoPlay', 'no', { expires: 365 * 10 });
                },
                'With Music': function() {
                    $(this).dialog('close');
                    $.cookie('autoPlay', 'yes', { expires: 365 * 10 });
                }
            }
        });
    });

Can you spot the error? It's in the first line: the <script tag isn't closed. It should be <script type="text/javascript">

My previous suggestion still stands, however: you should enclose intra-tagged scripts in a CDATA block, or move them to a separately linked file.

That wasn't the issue here, but it would have shown the real issue faster.

I too got this error, when developing a Backbone application using HTML5 push state in conjunction with an .htaccess which redirects any unknown files to index.html.

It turns out that when visiting a URL such as /something/5, my /index.html was effectively being served at /something/index.html (thanks to my .htaccess). This had the effect of breaking all the relative URLs to my JavaScript files (from inside the index.html ), which meant that they should have 404'd on me.

However, again due to my htaccess, instead of 404'ing when attempting to retrieve the JS files, they instead returned my index.html. Thus the browser was given an index.html for every JavaScript file it tried to pull in, and when it evaluated the HTML as if it were JavaScript, it returned a JS error due to the leading < (from my tag in index.html).

The fix in my case (as I was serving the site from inside a subdirectory) was to add a base tag in my html head.

<base href="/my-app/">

I had the exact same symptom, and this was my problem, very tricky to track down, so I hope it helps someone.

I was using JQuery parseJSON() and the content I was attempting to parse was actually not JSON, but an error page that was being returned.

Typically this happens when you are trying to load a non-html resource (e.g the jquery library script file as type text/javascript) and the server, instead of returning the expected JS resource, returns HTML instead - typically a 404 page.

The browser then attempts to parse the resource as JS, but since what was actually returned was an HTML page, the parsing fails with a syntax error, and since an HTML page will typically start with a < character, this is the character that is highlighted in the syntax error exception.

After trying several solutions, this worked for me:

1. Go to IIS Manager
2. Open the Site
3. Click on Authentication
4. Edit Anonymous Authentication.
5. Select "Application pool identity"