javascript - How to load a js file before opening the website?

Question

Moreover, after the website is loaded and opened normally, the code for loading js is not displayed in the web page code. Can this be done? ? ? Solve

大家讲道理 · Answer

I don’t know how the questioner defines it before the website is opened?

If you just want the web page to load js files earlier, you can put the script reference in the head tag.
However, the question also requires that the web page code does not display the js after opening. This is how I understand it. In this case, there are two main steps:

Write an inline js code in the head tag. The main function of the code is to introduce the js file and follow-up actions
The so-called follow-up action is to trigger the loading event after introducing the file to remove the introduction of the file from the document dom

I will simply list a demo:

First prepare the page t.html




    
    waterfall

Introduced js: t.js

(function(){
    console.log('hello i am t');
})()

I wonder if this is the main effect of the question?

ringa_lee · Answer

If you want to improve the loading speed, you can use cache to load js in advance. I have never encountered this before

世界只因有你 · Answer

Use a web server (such as nginx) to insert content into the page?
Then this js is also monitoring whether the page has been loaded, and deletes itself after loading.

PHP中文网 · Answer

Try putting the actual web page in the iframe and js outside the iframe?