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POCode not executing in img.onload
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  1. POCode not executing in img.onload
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    copied!<p><code>alert('loaded');</code> is never executed in the first code snippet.<br/> The only difference between the 2 code snippets is <code>alert('setting src..');</code> is commented out in first example, but left in the 2nd example.<br/> Why is <code>alert('loaded');</code> not executed in first example?</p> <p>I have a html file, containing a form, when the form is submitted <code>Utils.imgExists()</code> is called.<br/> <code>Utils.imgExists()</code> is declared in a JS file, included in the html document.</p> <pre><code> &lt;form action="anotherPage.html" method="get" onsubmit="return Utils.imgExists('http://www.nasa.gov/images/content/711375main_grail20121205_4x3_946-710.jpg')"&gt; &lt;div id="imageInput"&gt; &lt;input type="text" id="image" name="image" value="http://www.nasa.gov/images/content/711375main_grail20121205_4x3_946-710.jpg" title="Paste an image URL e.g http://server.com/path/to/image.jpg"/&gt; &lt;/div&gt; &lt;button type="submit"&gt;Submit&lt;/button&gt; &lt;/form&gt; </code></pre> <p><code>Utils.imgExists()</code> inside Utils.js:</p> <pre><code>var Utils = { imgExists: function(url){ function imgExists(url, callback) { alert('in imgExists'); var img = new Image(); img.onerror = function() { alert('error'); callback(false); }; img.onload = function () { alert('loaded'); callback(true); }; img.src = url; //alert('setting src..'); } function checkImage(exists) { alert("Image exists: " + exists); } imgExists('http://www.nasa.gov/images/content/711375main_grail20121205_4x3_946-710.jpg', checkImage); } }; </code></pre> <p>This is the second example:</p> <pre><code>var Utils = { imgExists: function(url){ function imgExists(url, callback) { alert('in imgExists'); var img = new Image(); img.onerror = function() { alert('error'); callback(false); }; img.onload = function () { alert('loaded'); callback(true); }; img.src = url; alert('setting src..'); } function checkImage(exists) { alert("Image exists: " + exists); } imgExists('http://www.nasa.gov/images/content/711375main_grail20121205_4x3_946-710.jpg', checkImage); } }; </code></pre>
 

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