Undeclared variable can be assigned in strict mode if html element with same id
Categories
(Core :: DOM: Core & HTML, task, P3)
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(Reporter: FormularSumo, Unassigned)
Details
User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:130.0) Gecko/20100101 Firefox/130.0
Steps to reproduce:
Run the following test case code
<!DOCTYPE html>
<html>
<body>
<div id='test'></div>
<script>
"use strict";
test = "text";
console.log(test)
</script>
</body>
</html>
Actual results:
Firefox allows the variable test to be assigned without being declared using a keyword. This is because test is also the id of a html element, and prior to being (re-)assigned is a reference to that element. After (re-)assigning test, it can be set to any other value such as in this case "text", even though it hasn't been declared in the Javascript code.
Expected results:
When strict mode is on, references to html elements shouldn't be able to be (re-)assigned without a variable declaration. This is the current behaviour in Chromium-based browsers, which is what led me to notice this. I'd forgotten to use a "let" declaration in a project, and Firefox (and Webkit-based browsers) ran the code fine in strict mode, while Chromium ones returned "Uncaught ReferenceError: test is not defined", which I think is the correct behaviour here.
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Comment 1•1 year ago
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This is probably better placed into "DOM: Core & HTML", because it involves Named Properties which is a HTML thing.
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Reporter | |
Updated•1 year ago
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Comment 2•1 year ago
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Peter, who would be the right person to look into this?
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Comment 3•1 year ago
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So I think Chrome is not following the spec here, these properties are writable and configurable https://webidl.spec.whatwg.org/#named-properties-object-getownproperty:~:text=Set%20desc.%5B%5BWritable%5D%5D%20to%20true%20and%20desc.%5B%5BConfigurable%5D%5D%20to%20true. File a spec bug if you think this behaviour should change.
I'll leave this open so we can add a wpt.
Description
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