How to load google-analytics (or other third party) JS_javascript tips

After registering ga, ga will generate a js script. Many people directly copy this js to the end of

(including Blog Park, CSDN, BlogJava). But is this JS automatically generated by ga really the most reasonable?

What is reasonable and what is unreasonable? Because ga is just an analysis tool, its use must not affect our program. If it does, it is unreasonable. It is reasonable if it does not affect it.

Current use of ga:
First look at the js script automatically generated by ga, as follows:

Copy code The code is as follows:

"));

Look at this code and use document.write to load JS. Note that loading js in this way will block the loading, that is, this js has not been loaded, and all subsequent resources and JS Neither can be downloaded and executed. You may think that this code is at the end of the body, and there is no content at the end, so there is nothing that will block it.
There are some things you have overlooked. I believe many people need to execute some JS or AJAX after the page is loaded when writing JS. Generally, they are written in the window.onload event, or written in jquery's $(document).ready( ) method. These JS will be blocked. If a lot of data on our page is loaded using AJAX in window.onload, but at this time ga cannot access it for some reasons (Harmony and Harmony), or the access is very slow. The problem is that our own JS has been waiting for ga's JS to be loaded, and our JS will only be executed after ga's js loading times out.

Example:
The following code uses jquery to send an ajax request (request 126.com) in document.ready. Modify the host file before testing so that ga's js cannot be loaded:

Copy code The code is as follows:

"));

Monitoring picture:

As can be seen from the above picture, ga cannot be loaded. After a 20-second timeout, our ajax request is executed. Our ajax request only takes 0.173s, but it waits. 20s.
Use ga properly:

To use ga properly, you need to solve 2 problems:
1. How to non-load ga’s js,
2. How to use ga in ga Immediately after the ja is loaded, execute the var pageTracker = _gat._getTracker("UA-123456-1"); pageTracker._trackPageview(); code.

There are two main ways to load js non-blockingly:
1. Dynamically create

The above code is modified from jquery’s ajax code. The above code is easy to understand. It dynamically creates a script to load js, and executes the code after loading through onload or onreadystatechange events.

After the code modification is completed, monitor and test as follows;

It can be seen from the picture that ga still loaded for 20s, but our ajax request did not wait for 20s to be executed, but was executed immediately.

jquery loads ga:

Maybe you think the above code is too much to write and cumbersome. If you use jquery, it can be simplified as follows:

Copy code The code is as follows:

var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http:// www.");
$.getScript(gaJsHost "google-analytics.com/ga.js",function(){
try {
var pageTracker = _gat._getTracker("UA-123456-16 ");
pageTracker._trackPageview();
} catch(err) {}
});

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