element.length

概要

lengthはNodeList内のitemの数を返します。

構文

numItems =nodeList.length

• numItems はNodeList内のitem数に相当する 整数値(integer)です。

例

// all the paragraphs in the document 
var items = document.getElementsByTagName("p"); 
// for each item in the list,
// append the entire element as a string of HTML
var gross = "";
for (var i = 0; i < items.length; i++) {
  gross += items[i].innerHTML;
}
// gross is now all the HTML for the paragraphs

注意

Despite the location of this page in the reference, length is not a property of Element, but rather of a NodeList. NodeList objects are returned from a number of DOM methods, such as document.getElementsByTagName.

length is a very common property in DOM programming. It's very common to test the length of a list (to see if it exists at all) and to use it as the iterator in a for loop, as in the example above.

仕様

length