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Does JavaScript have collections?
- 醉折花枝作酒筹Original
- 2021-07-16 11:43:372667browse
There are collections in JavaScript. The HTMLCollection object in JavaScript is an array-like list (collection) of HTML elements. The getElementsByTagName() method returns an HTMLCollection object.
The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.
There are collections in JavaScript. The HTMLCollection object in JavaScript is an array-like list (collection) of HTML elements. The getElementsByTagName() method returns an HTMLCollection object.
DOM collection in JavaScript:
The length attribute defines the number of elements in the HTMLCollection:
Example:
<!DOCTYPE html>
<html>
<body>
<h1>JavaScript HTML DOM</h1>
<p>Hello World!</p>
<p>Hello China!</p>
<p id="demo"></p>
<script>
var myCollection = document.getElementsByTagName("p");
document.getElementById("demo").innerHTML =
"此文档包含 " + myCollection.length + " 段文字。";
</script>
</body>
</html>Effect:
Explanation of examples:
Create a collection of all
elements
Display the length of the collection
Note:
HTMLCollection is not an array!
HTMLCollection may look like an array, but it is not an array.
You can iterate over a list and reference elements numerically (just like an array).
However, you cannot use array methods such as valueOf(), pop(), push(), or join() on HTMLCollection.
[Recommended learning: javascript advanced tutorial]
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