I'm trying to shim Element.prototype.children
which should return a HTMLCollection
There is a window.HTMLCollection
However
var h = new HTMLCollection();
//TypeErrror: HTMLCollection is not a constructor
and
var h = Object.create(HTMLCollection.prototype);
h[0] = div;
h.item(0);
// Could not convert JavaScript argument
Test Firefox 7 and Chrome
Apart from shimming HTMLCollection
is there any way to interact with it?
Also provide feedback on this github issue if you can suggest a solution
Here's how I would do it:
function MyHTMLCollection( arr ) {
for ( var i = 0; i < arr.length; i += 1 ) {
this[i] = arr[i];
}
// length is readonly
Object.defineProperty( this, 'length', {
get: function () {
return arr.length;
}
});
// a HTMLCollection is immutable
Object.freeze( this );
}
MyHTMLCollection.prototype = {
item: function ( i ) {
return this[i] != null ? this[i] : null;
},
namedItem: function ( name ) {
for ( var i = 0; i < this.length; i += 1 ) {
if ( this[i].id === name || this[i].name === name ) {
return this[i];
}
}
return null;
}
};
where arr
is a regular array that contains all the DOM elements which should be inside the HTMLCollection.
To do list:
- the argument
arr
should be checked beforehand: Is it an array? Are all elements of that array DOM elements?
Don't expect host objects to behave like (ECMAScript) native objects, they are completely different things. Some browsers do implement their DOM objects like ECMAScript objects, but it is not required and should not be relied upon. Note that most HTML collections are live, it is very difficult to emulate that in a native object.
I know this is an older question but I came across a similar need to create an empty HTMLCollection and I did it by simply creating an element and then running getElementsByClassName() against it using a class that doesn't exist in the element.
document.createElement("div").getElementsByClassName('noClassHere');
This returns an empty HTMLCollection object.
来源:https://stackoverflow.com/questions/7754269/create-a-htmlcollection