length
returns the number of items in a NodeList
.
numItems = nodeList.length
numItems
is an integer value representing the number of items in a NodeList
.// 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
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.
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https://developer.mozilla.org/en-US/docs/Web/API/NodeList/length