In JavaScript code, the random number is added after the ajax request address to prevent browser caching.

When someone else writes JavaScript code, add random parameters to the ajax request address, such as XXXX? T = + new Date (). getTime ().

At first, I couldn't understand why. I checked the information on the Internet because it prevented browser caching.

The browser caches page data to speed up user access to the same page. When the url request address remains unchanged,

Sometimes, the browser does not send a request and reads the previous data directly from the cache.

If the data changes without adding a random number, the read data will be the same as before.

When a random number is added, the browser url is changed and a request is sent to the server without reading the cache.