length returns the number of items in a NodeList.


numItems =
  • 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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 Last updated by: fscholz,