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POJavascript event listening differs depending on use of anonymous or named function
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  1. POJavascript event listening differs depending on use of anonymous or named function
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    copied!<p>I'm using the following code to duplicate the input of one textarea in another:</p> <pre><code>/** * Copies the values entered into the old description * into the new description, until the user focuses * on the new description */ var DescriptionLinker = (function() { var elOldDescription, elNewDescription, linkIsBroken; this.init = function() { console.log('Initializing DescriptionLinker'); elOldDescription = document.getElementById("old-description"); elNewDescription = document.getElementById("new-description"); linkIsBroken = false; linkDescriptions(); watchLinkBreak(); } // Assigns values to 'this' var finalize = function() { this.elOldDescription = elOldDescription; this.elNewDescription = elNewDescription; } var linkDescriptions = function() { elOldDescription.addEventListener("keyup", linkListener(), false); } var unlinkDescriptions = function() { elOldDescription.removeEventListener("keyup", linkListener(), false); } var linkListener = function(){ elNewDescription.value = elOldDescription.value; } var watchLinkBreak = function() { console.log("Watching for link break"); elNewDescription.addEventListener("focus", function(){ unlinkDescriptions(); }); } finalize(); return this; })(); DescriptionLinker.init(); </code></pre> <p>The code works, however the values do not appear in <code>&lt;textarea id="new-description"&gt;&lt;/textarea&gt;</code> until I focus on the text area. If I replace the call to <code>linkerfunction()</code> with an identical anonymous function then the values correctly appear in the <code>new-description</code> textarea as I type in the <code>old-description</code>. Any ideas why?</p> <p>To clarify, the following works correctly:</p> <pre><code>var linkDescriptions = function() { elOldDescription.addEventListener("keyup", function(){ elNewDescription.value = elOldDescription.value; }, false); } var unlinkDescriptions = function() { elOldDescription.removeEventListener("keyup", function(){ elNewDescription.value = elOldDescription.value; }, false); } </code></pre> <p>PS reason for all this is transition from a legacy system :p</p>
 

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