Before every ajax request using jQuery, I want to do sth

means, do sth, then request using jQuery, like a hook开发者_StackOverflow社区er. How can i do this?

Use $.ajaxSetup() for this

Full documentation here

For example:

$.ajaxSetup({
    beforeSend: function() {
       //do something, like show 'Requesting....'
    }
});