AJAX prevents code cached by pages

When AJAX technology is used, we usually use the same url to retrieve data after refreshing the page to submit data, and we will find that the data is from the past ~ This creates an illusion for the client ~~ You can cancel the cache using the following methods:
Htm webpage
<Metahttp-equiv = "pragma" content = "no-cache">
<Metahttp-equiv = "cache-control" content = "no-cache, must-revalidate">
<Metahttp-equiv = "expires" content = "wed, 26feb199708: 21: 57gmt">
Or <metahttp-equiv = "expires" content = "0">
Asp Web Page
Response. expires =-1
Response. expiresabsolute = now ()-1
Response. cachecontrol = "no-cache"
Php webpage
Header ("expires: mon, 26jul199705: 00: 00gmt ");
Header ("cache-control: no-cache, must-revalidate ");
Header ("pragma: no-cache ");
Jsp webpage
Response. addHeader ("pragma", "no-cache ");
Response. addHeader ("cache-control", "no-cache, must-revalidate ");
Response. addHeader ("expires", "0 ");