调用 function onload 外部脚本

Question

I'm playing around with Google Drive API, and noticed that they are calling a handleClientLoad function onload of the client.js.

<script src="https://apis.google.com/js/client.js?onload=handleClientLoad"></script>

Trying to avoid creating globals, I thought I would start with creating another js file, that would contain a module pattern and return handleClientLoad .

var module = (function (window, $) {

    'use strict';

     var module = {
         handleClientLoad: function () {
             console.log('ok, can access');
         }
     };

     return module;

}(window, jQuery));

And then I assumed I could just call the handleClientLoad by doing module.handleClientLoad , but that doesn't seem to be working.

    <script src="scripts/main.js"></script>
    <script src="https://apis.google.com/js/client.js?onload=module.handleClientLoad"></script>

Questions:

1. Is it possible to call the module.handleClientLoad from onload of client.js?

2. Appending onload and calling a function from a script file seems sloppy and obtrusive, no? Is there a cleaner way to know when the client.js has loaded?

Answer 1

1. Have you tried debugger, and are you sure module. hanfleClientLoad exists at the time the callback is fired?

2. You can poll for the existence of gapi.client as a global object. Give it a few milliseconds to initialise before invoking its methods.

Answer 2

I found that jQuery.getScript() worked quite nicely for this. Documentation here .

Instead including the <script> tag in the html page, I simply included the following line in my js file:

jQuery.getScript( "https://apis.google.com/js/api.js", handleClientLoad );

It might require slight tweaking for the way you structured your module, but I think this will be easier than passing a parameter to your <script> tag (at least I found it easier).

Answer 3

I know this is old, but I was messing around with this because this was related to a question on a test I was studying for. You can use onload like this when you call the script:

<script src="https://apis.google.com/js/client.js" onload="handleClientLoad()"></script>

For anyone wanting to know why this won't work:

<script src="https://apis.google.com/js/client.js">handleClientLoad()</script>

It's because any code between a script tag with "src=" in it will be ignored.

And I'm not sure why using onload= in the script tag calling the external script is any more obtuse than appending?onload=module.handleClientLoad to the source? But that's just me.

In the end, I'm not sure why exactly this was a question on the test, because based on searching, this doesn't seem to be a common thing that anyone does.