$(…).each is not a function

问题:

I'm trying to get the text inside all h2 tags on a page, using the web console.

All I've found says to use each, I've tried

var anArray = [];

$('h2').each( function(i,e) {
    anArray.push($(e).innerHTML);
});

But it returns TypeError: $(...).each is not a function.

I've also tried using

$.each('h2', function(i,e) {
        anArray.push($(e).innerHTML);
    });

But again, all I get is TypeError: $.each is not a function?

回答1:

1) Paste:

var script = document.createElement('script');
script.src = "https://ajax.googleapis.com/ajax/libs/jquery/1.6.3/jquery.min.js";
document.getElementsByTagName('head')[0].appendChild(script);

on your console (includes jQuery)

2) Wait 1 sec and paste:

var h2Arr = [];
$('h2').each( function() {
    h2Arr.push($(this).html());
});

Now, all contents of h2 tags of that page should be stored into h2Arr

回答2:

if you write code like without $() for example

var1.each(function(){}) //its wrong//each function is not defined error

$(var1).each(function(){}) //its right

回答3:

Note: For Chrome, do not expect $ is always jQuery.

You can put $ into console to check if it returns default ƒ $(selector, [startNode]) { [Command Line API] }, if yes means $ is not defined for jQuery.

Luckily that we have below ways to try:

1. Solve the conflict of using $, let it be jQuery without any ambiguity

Firstly, you can put this code snippet

var jq = document.createElement('script');
jq.src = "https://code.jquery.com/jquery-3.3.1.min.js";  /* Include any online jquery library you need */
document.getElementsByTagName('head')[0].appendChild(jq);

into the Console, then put $.noConflict into console, if it not returns undefined, but returns ƒ (t){return e.$===w&&(e.$=Kt),t&&e.jQuery===w&&(e.jQuery=Jt),w}, it means $ is not defined for JQuery now.

Next you can continue to input your regional code, then you will find it works well now.

Refer: https://blog.wplauncher.com/run-jquery-in-chrome-console/

2. Using .js file instead in Chrome, then debug the JavaScript file.

Refer: Chrome DevTools Snippets

3. Besides, for some specific version of Chrome, there is a option in UI to set the page context (probably removed this function in latest version!)

.

回答4:

You have to use .html() instead of .innerHTML:

$.each($('h2'), function(index, value){
   alert($(value).html());
});

Here a working fiddle.

回答5:

The most common cause of this error is because JQuery is not included in your website, that's why it shows this error. You have to include JQuery in your website or rewrite your code in vanilla js.