Re: Is jQuery worth a second look?

Oltmans wrote:
On Sep 30, 6:38 pm, "Thomas 'PointedEars' Lahn" <PointedE...@xxxxxx>
wrote:
kangax wrote:
dhtml wrote:
isFunction - still uses function decompilation. Kangax posted on
es-discuss that that was changed but I still see the isFunction in the
latest 1.2.6.
Garrett,
their trunk is using `instanceof` [1].
Irrelevant, except that it shows their cluelessness.


Why using "instanceof" considered to be not so good? Can you please
explain it to me with a few examples? That will be highly appreciated.


Instanceof won't work like you want it to across frames. This is because self.Function != frames[0].Function.

frames[0].fun instanceof Function will return false across frames.
Two documents example:
document1.html
myframe.html:


document1.html:
<body>
<iframe src="myframe.html"></iframe>

<script>
onload = function() {
var f = frames[0].fun;
document.write(['<pre>',f instanceof Function, f].join('\n'));
document.close();
};
</script>

</body>


myframe.html:
<script>
function fun() {}
</script>

Result:
false
function fun() {
}

So we can see that instanceof won't work across frames like you'd want it to, and the isFunction uses instance of.

Garrett
.

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