JS dynamic insertion and immediate execution of callback functions _ javascript skills

This article describes how to dynamically insert JS files and execute callback functions immediately. The example shows how to dynamically insert js files and execute callback functions, for more information about how to dynamically insert JS data and immediately execute the callback function, see the example in this article. We will share this with you for your reference. The details are as follows:

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Dynamic insertion of js files plays an important role in improving page loading speed and Cross-Domain issues. The above is a simple example.

Onreadystatechange is supported on ie, and onload is not supported.

Onload is supported on firefox, and onreadystatechange is not supported.

In ie, it is not necessarily triggered by loaded or complete, or both of them are triggered, so it is determined by or.

Note that script. onreadystatechange and script. readyState are case-insensitive, which may lead to hard-to-find errors.