- From: Daniel Holbert via GitHub <sysbot+gh@w3.org>
- Date: Wed, 07 Jun 2017 20:01:59 +0000
- To: public-css-archive@w3.org
Possibly-more-direct testcase:
````
<style id="styles">
div { font-family: AAA }
</style>
<script>
var rule = document.getElementById("styles").sheet.cssRules[0];
var styleCopy = rule.style; // THE QUESTION: How "live" is styleCopy?
console.log("Initial: " + styleCopy.fontFamily);
// Tweak rule.style.* and see if it's visible in styleCopy:
rule.style.fontFamily = "BBB";
console.log("After tweaking rule.style.fontFamily: " + styleCopy.fontFamily);
// Tweak rule.style itself, and see if it's visible in styleCopy:
rule.style = "font-family: CCC";
console.log("After tweaking rule.style: " + styleCopy.fontFamily);
// Clear rule.style and see if it's visible in styleCopy:
rule.style = "";
console.log("After clearing rule.style: " + styleCopy.fontFamily);
</script>
````
In Firefox 55 Nightly & Chrome Dev 60, this outputs:
> Initial: AAA
> After tweaking rule.style.fontFamily: BBB
> After tweaking rule.style: CCC
> After clearing rule.style:
In Safari 10.1 & Edge 15, this instead outputs:
> Initial: AAA
> After tweaking rule.style.fontFamily: BBB
> After tweaking rule.style: BBB
> After clearing rule.style: BBB
The last two lines are where we differ -- specifically, browsers disagree about what happens when you adjust the value of `CSSStyleRule.style` (though they agree on what happens when `CSSStyleRule.style.whatever` is tweaked.)
* In Firefox & Chrome, `CSSStyleRule.style` seems to be a reference to an object, and if you reassign it, you're updating the contents of that object (which is reflected in variables that were set to the original value).
* In Edge & Safari, `CSSStyleRule.style` behaves more like a *pointer* to an object, and reassignment will simply change `CSSStyleRule.style` to point somewhere else (and that change is *not* reflected in variables that were set to the original value).
--
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Received on Wednesday, 7 June 2017 20:02:05 UTC