google chrome - Javascript: Handle GET Error (document.createElement) - Stack Overflow

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I'm trying to 'include' a JS file to my document. It works fine, but when the file is offline, it should set a variable to FALSE. I googled it, but I didn't get it. So I tried it with the try/catch:

    try {
      var jq = document.createElement('script');
      //jq.onload = put;
      jq.type = 'text/javascript';
      jq.src = 'http://127.0.0.1:9666/jdcheck.js';
      document.getElementsByTagName('head')[0].appendChild(jq);
    }
    catch(e) {
    console.log('An error has occurred: '+e.message);
        jdownloader = false;

    }

It just throws me the error

  Failed to load resource http://127.0.0.1:9666/jdcheck.js

How is it possible to set the var to FALSE?

Thank you, Markus

I'm trying to 'include' a JS file to my document. It works fine, but when the file is offline, it should set a variable to FALSE. I googled it, but I didn't get it. So I tried it with the try/catch:

    try {
      var jq = document.createElement('script');
      //jq.onload = put;
      jq.type = 'text/javascript';
      jq.src = 'http://127.0.0.1:9666/jdcheck.js';
      document.getElementsByTagName('head')[0].appendChild(jq);
    }
    catch(e) {
    console.log('An error has occurred: '+e.message);
        jdownloader = false;

    }

It just throws me the error

  Failed to load resource http://127.0.0.1:9666/jdcheck.js

How is it possible to set the var to FALSE?

Thank you, Markus

• javascript
• google-chrome
• error-handling
• createelement

Share Improve this question Follow edited Jun 4, 2014 at 12:04 Raidri 17.6k1111 gold badges6666 silver badges6868 bronze badges asked Oct 4, 2013 at 13:02 StandardStandard 1,52211 gold badge1717 silver badges3939 bronze badges 3

• jdownloader will be false when catch clause is executed. what do you want exactly – Rajesh Commented Oct 4, 2013 at 13:06
• Do you really get an error thrown? Could it be that this is just a warning? For then the catch block will never execute. – Wolfgang Kuehn Commented Oct 4, 2013 at 13:07
• You may use the onload event on the script tag. If it never fires, then the resource could not be loaded. – Wolfgang Kuehn Commented Oct 4, 2013 at 13:10

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1 Answer 1

Sorted by: Reset to default 7

You're sort of doing it wrong. When checking if a script source can be loaded, there are built in onload and onerror events, so you don't need try / catch blocks for that, as those are for errors with script execution, not "404 file not found" errors, and the catch part will not be executed by a 404 :

var jq = document.createElement('script');
jq.onload = function() {
    // script loaded successfully
}

jq.onerror = function() {
    // script error
}

jq.type = 'text/javascript';
jq.src = 'http://127.0.0.1:9666/jdcheck.js';
document.getElementsByTagName('head')[0].appendChild(jq);

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