[BATIK-321] "this" value is not always available in EventListener

• Type: Bug
• Status: Resolved
• Resolution: Incomplete
• Affects Version/s: 1.5
• Component/s: Scripting
• Environment: Operating System: Windows XP; Platform: PC
• Assignee: Batik Developer's Mailing list
• Reporter: Samuel C. Yang
• Created: 16/Oct/02 17:43
• Updated: 16/Nov/04 19:05
• Resolved: 16/Nov/04 19:05

Description

I was trying to use the following ECMAScript with Batik 1.5 beta 4's Squiggle,
but I noticed some inconsistent behavior:

========= START CODE =========
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "//W3C//DTD SVG 1.0//EN" "http://www.w3.org/TR/2001/REC
SVG-20010904/DTD/svg10.dtd">
<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" id="testSVG">
<script type="text/ecmascript"><![CDATA[
function TestObj()
{
this.root = document.documentElement;
this.abc = 123;
this.myFunc = function()

{ alert(this.abc); }

this.root.addEventListener("click", this.myFunc, false);
}
var obj = new TestObj();
]]></script>
<rect width="100%" height="100%" fill="green"/>
<rect x="45%" y="45%" width="10%" height="10%" onmouseover="obj.myFunc()"/>
</svg>
========= END CODE =========

When addEventListener() is explicitly called to add the TestObj.myFunc method
as an event listener, and myFunc gets called as the result of an event,
the "instance variable" this.abc is undefined. However, if I add the same
function as an event listener via an onmouseover attribute, that instance
variable is defined. This inconsistent behavior exists Adobe's viewer as well.

To see the undefined variable behavior, click anywhere in the SVG window. To
see the "proper" behavior, mouse over the black rectangle.

It seems to me the click behavior should be the same as the mouseover behavior.

Probably, addEventListener() is treating its function argument as a simple
function instaed of an object method.