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POChrome extension: inserting a javascript tag and calling a function
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  1. POChrome extension: inserting a javascript tag and calling a function
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    copied!<p>I have a chrome extension that uses a <strong>content script</strong> in order to dynamically insert a script tag referencing <a href="http://unixpapa.com/js/dyna1.js" rel="nofollow">an external javascript file</a>. The code I use is:</p> <pre><code>var html_doc = document.getElementsByTagName('head')[0]; var _js = document.createElement('script'); _js.setAttribute('type', 'text/javascript'); _js.setAttribute('id', 'chr_js'); _js.setAttribute('src', 'http://unixpapa.com/js/dyna1.js'); if(!document.getElementById('chr_js')) html_doc.appendChild(_js); </code></pre> <p>The external Javascript contains the following code:</p> <pre><code>function lfunc(){ alert('RUNNING loaded function'); } alert('LAST LINE of script'); </code></pre> <p>When I load a page in a tab the "<em>LAST LINE of script</em>" message appears, showing that the script tag is correctly inserted in the DOM. </p> <p>My extension also has a <strong>button</strong> (i.e., a browser_action). Now, I would like this button to call <em>lfunc()</em> defined above whenever it is clicked. Unfortunately, <strong>my code simply doesn't work</strong>.</p> <p>I use the following code in the <em>background.html</em> page to process the onClick event of my button:</p> <pre><code>&lt;script&gt; chrome.browserAction.onClicked.addListener(function(tab) { chrome.tabs.executeScript(null, {code: "try {lfunc()} catch (e) {alert(e);}"}); }); // it should call lfunc() &lt;/script&gt; </code></pre> <p>The permissions in the <em>manifest.json</em> file are:</p> <pre><code>"permissions": [ "tabs", "http://*/*", "https://*/*" ] </code></pre> <p>Instead of getting the "<em>RUNNING loaded function</em>" message I get the error message "<em>ReferenceError: lfunc is not defined</em>". </p> <p>What am I doing wrong?</p>
 

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