Closed
Bug 489153
Opened 16 years ago
Closed 15 years ago
appendChild(<script src=...>) executes the appended script asynchronously (Newly added JavaScript function cannot be called in same thread)
Categories
(Core :: General, defect)
Tracking
()
RESOLVED
INVALID
People
(Reporter: anschoen, Unassigned)
Details
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.8) Gecko/2009032609 Firefox/3.0.8
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.8) Gecko/2009032609 Firefox/3.0.8
The following HTML page adds a new external JavaScript file to the page when one of boxes is clicked:
<html>
<head>
<script type="text/javascript">
function addExternalScript(url) {
var scriptTag = document.createElement("script");
scriptTag.setAttribute("type","text/javascript");
scriptTag.setAttribute("src",url);
document.getElementsByTagName("head")[0].appendChild(scriptTag);
}
</script>
</head>
<body>
<div style="background-color:blue;width:100px;height:100px" onclick="addExternalScript('script.js');f1();">Click to call external function in the same thread that added the script</div>
<div style="background-color:yellow;width:100px;height:100px" onclick="addExternalScript('script2.js');setTimeout('f2()',1);">Click to call external function in a different thread</div>
</body>
</html>
In the first case, the a function in the newly included file is invoked right after the JavaScript file was added. In the second case, a "new thread" was used to call the external function. Only the second case works.
Used scripts:
script1.js:
function f1() {
alert("hello");
}
script2.js:
function f2() {
alert("hello");
}
Reproducible: Always
Steps to Reproduce:
1.Click on first box in page
2.
3.
Actual Results:
Nothing happens
Expected Results:
An alert box should be shown.
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Updated•16 years ago
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Product: Firefox → Core
QA Contact: general → general
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Reporter | |
Updated•15 years ago
|
Severity: minor → major
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Comment 1•15 years ago
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Sorry you were ignored. These things happen, unfortunately, and you should feel free to post to a relevant mailing list or ask in IRC to bring attention to your problem.
As for the problem itself. I can reproduce it, but it's by design. Note that every other browser does this (I checked Chrome and Opera on Mac) and it's described in the HTML5 spec: http://www.whatwg.org/specs/web-apps/current-work/multipage/scripting-1.html#running-a-script
[...]
8. Then, the first of the following options that describes the situation must be followed:
[...]
-> If the element has a src attribute
The element must be added to the end of the list of scripts that will execute as soon as possible.
[... note that <script>inline script</script> is executed synchronously]
-> Otherwise
The user agent must immediately execute the script block, even if other scripts are already executing.
You might be also interested in tests (showing the behavior we expect) -- added in bug 371576. E.g. http://mxr.mozilla.org/mozilla-central/source/content/base/test/test_bug371576-1.html?force=1 tests, in particular, your case ("B" directly following "A")
Status: UNCONFIRMED → RESOLVED
Closed: 15 years ago
Resolution: --- → INVALID
Summary: Newly added JavaScript function cannot be called in same thread → appendChild(<script src=...>) executes the appended script asynchronously (Newly added JavaScript function cannot be called in same thread)
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Description
•