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POHow to report JS-Errors from Script at different domain?
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copied!<p>I'm currently trying to report all uncatched JS errors like this with jquery:</p> <pre><code>window.onerror = function(msg, file, line) { $.post("https://"+current_url+"/js_error", { msg: msg file: file line: line }); } </code></pre> <p><code>current_url</code> is always the domain I am currently at.</p> <p>When I am at <code>www.website.com</code> and the script is loaded from <code>www.website.com/script.js</code> (same domain), everything works fine. I tried it with a undefined variable, and get the correct message <code>variable is undefined</code> postet to <code>https://www.website.com/js_error</code>.</p> <p>Now, I have some subdomains: <code>a.website.com</code>, <code>b.website.com</code> etc. All of them have different content, but use exactly the same javascript.</p> <p>My idea was the following: Always include the javascript from <code>www.website.com</code>, so that when you switch the subdomain, the script can be cached by browsers and does not have to be redownloaded again.</p> <p>But unfortunately this breaks the error reporting above. When the script is included from a different domain, e.g. I am at <code>a.website.com</code> and include the script from <code>www.website.com/script.js</code>, I only get these errors posted to <code>https://a.website.com/js_error</code> (for firefox browsers):</p> <pre><code>"Script Error." on line 0 </code></pre> <p>I realize this is due to the same-origin policy, see <a href="https://stackoverflow.com/questions/5913978/cryptic-script-error-reported-in-javascript-in-chrome-and-firefox">this question</a>.</p> <p>I also tried to hardcode <code>current_url</code> to <code>www.website.com</code> (from where the script is loaded), so the POST goes always there regardless of the domain I am at. But this POST does not work at all from a different subdomain than <code>www.website.com</code> (I think because cross domain ajax POSTs are not possible).</p> <p>I also tried to send the error as a GET (<code>$.get</code>), but this always give me <code>"Script Error." on line 0</code> on a subdomain - regardless the target of the GET.</p> <p>So, how can I report errors for my script? I want to detect them so I can fix them, but do not want to give up the caching.</p> <p>BTW: I am using firebug to debug my scripts, so I detect errors when <em>I</em> get them. But due to the complexity it is not always possible to spot every error for every OS/browser combination, and I want make sure to detect them when they happen at my clients, too.</p> <p><strong>EDIT</strong>: jsfiddle deleted</p>

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