Javascript TypeError ____ is not a function

Question

I am currently using the Chrome console to do some debugging for a Greasemonkey script.

From the console I run var opp = document.querySelectorAll(\'a[class=\"F-re

Answer 1

querySelectorAll returns a NodeList. This is similar to an array (it has a .length property and you can index it with []), but it's not actually an array, and doesn't have most of the array methods. If you want to use array methods on an array-like object, you have to call the method explicitly:

Array.prototype.splice.call(opp, 0, 1);

or:

[].splice.call(opp, 0, 1);

However, another difference between arrays and NodeLists is that you can't modify NodeList in place, which .splice tries to do; you can only read them like arrays. You should just use .slice() to extract the parts you want. Or convert the NodeList to an array first, and then operate on that. See

Fastest way to convert JavaScript NodeList to Array?