Some experience on using the onload event of js_Basic knowledge

If I ask you what window.load and window.onload mean respectively, I'm afraid you will answer me: "Isn't this executed after the page is loaded?"
But the answer is not necessarily, it depends on how you use it. Take a look at the example
Example 1:

Copy the code The code is as follows:

< !DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">






You can’t see me when you see true

When you see the true pop-up box, you definitely don’t see “You can’t see me when you see true”, which means that the js execution has started before the page is loaded. . " -//W3C//DTD HTML 4.0 Transitional//EN">

You see me when you see true




When you see the true pop-up box, you will also see "When you see true, you see me." This is only triggered after the real page is loaded.
PS: It is recommended to use anonymous functions like onload events, that is, window.onload=function(){ShowMessage();}.

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