1.客户端 cookie
2.服务器端session
3.两者子间 cache。
4.javascript。
Javascript is a very strong tool to meet the demand of customers which are very difficult and complex questions.Maybe it is the main reason to create the Ajax.
my process
1.page onload ,onblur
2.windows.open
3.window.link.herf
4.document .
in the window.link.href=http://www.sohu.com; ,should recember the http
window.link.href=www.sohu.com;
the two method is different