javascript - Working with callbacks -

$('form#register').on('submit', function(e) {     e.preventdefault();     userauth(this);     // if done :     // if fail : b }); $('form#login').on('submit', function(e) {     e.preventdefault();     userauth(this);     // if done : x     // if fail : y });  function userauth(form) {     console.log( $(form).serialize() );     var request = $.ajax({         url: 'process.php',         cache: false,         type: 'post',         data: $(form).serialize()     });     request.done( function (msg) {         console.log(msg);     });     request.fail(function(jqxhr, textstatus) {         console.log(jqxhr, textstatus);     }); } 

how check done/fail in submit handlers?

yes, know requires basic understanding of callback , asynchronous execution of javascript. i've read quite few books , tutorials don't seem it. maybe example here help.

simplest way add callback parameters:

function userauth(form, donecallback, failcallback) {     console.log( $(form).serialize() );     var request = $.ajax({         url: 'process.php',         cache: false,         type: 'post',         data: $(form).serialize()     });     request.done(donecallback);     request.fail(failcallback); } 

and call as:

$('form#register').on('submit', function(e) {     e.preventdefault();     userauth(this, function(){         //i'm done     }, function(){         //i failed     }); }); 

keep in mind callback functions receive same arguments done , fail jquery. if don't want this, call them as:

request.done( function (msg) {     donecallback(); }); request.fail(function(jqxhr, textstatus) {     failcallback(); }); 

callback not difficult concept. keep in mind they're arguments ints, strings, regexps , on. they're happen function, they're callable.

edit answer comment

you can save value function in more 1 way:

var globalvariable;  userauth(this, function() {     var myvalue = 4; // local variable      globalvariable = myvalue;      window.explicitglobalvariable = myvalue; // same above, except haven't created variable beforehand      implicitglobalvariable = myvalue; // i'm omitting var keyword, leak global scope }) 

the downside using global variables code smell in cases. there ways avoid them, require more knowledge need achieve give example.