25. BOM events

1 Window load event onload

Similar to the document loading event described earlier , Before we looked for the elements in the window , Must be written below the creation element

Now I want to script Put it on top , Then I will use the window loading event onload

When the document content (html,css,JS) The window loading event will be triggered after the complete loading ( The document loading event puts html After loading, it will trigger , That is to say, the execution sequence of document loading events is higher than that of window loading events )

Let's put script Move it up

Discovery can take effect

window.onload It is a traditional registration method , If you want to register multiple , Then you have to use window.addEventListener('load',function(){})

2   Window resizing Events onresize

This event will be triggered when the window is resized

When we resize the window, we specify multiple functions

• Press... Directly after opening the page F12 This event will also be triggered , Because a little more will change the size of the browser

It is usually done according to the screen size , For example, drag the screen size to a certain size , I just let the background change color

• We go through window.innerWidth To get the current browser width ,window.innerHeight You can get the current browser height

It is white after opening

Drag it casually to turn it into cyan , Because the width is less than 900

When dragging to greater than 900 Turns red when