JavaScript settimeout after deep recursive settings are complete callback

SetTimeout at execution time, after the specified time, after loading, to execute an expression, execute once
SetTimeout at execution time, it executes an expression at a specified time, after it has been loaded

1, Basic usage:
Execute a piece of code:

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VAR i=0;    settimeout ("I+=1;alert (i)", 1000);    execute a function:    var i=0    settimeout (function () {I+=1;alert (i);},1000);      //Note the difference between the two methods above.    One more execution function:    var i=0;    function Test () {    & nbsp;   i+=1;        alert (i);   }    settimeout ("Test ()", 1000);    can also be like this:    settimeout (test,1000);

Summarize:
The prototype of settimeout is this:

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Itimerid = Window.settimeout (Vcode, Imilliseconds [, Slanguage]) There are two forms of settimeout SetTimeout (Code,interval) SetTimeout (Func,interval,args)

Where code is a string
Func is a function.

Note that the meaning of "function" is an expression, not a statement.
Like you want to perform a function periodically

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function A () { //... } can be written as SetTimeout ("A ()", 1000) Or SetTimeout (a,1000)

Note that in the second form, it is a, do not write a (), remember!!!

In JavaScript, give a deep recursive setting that uses settimeout, and then callback after completion

Problem:

Because the recursion is too deep and the use of asynchronous settimeout clean air-conditioning stack, the entire recursive into asynchronous behavior, the function has been returned in advance, now how to set the entire recursive completion of the callback?

Reply:

Read the question to understand your meaning, I wrote for your purpose can debug the code, you look at the problem with the code is not the same:

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No callback function IsArray (o) { return tostring.apply (o) = = ' [Object Array] '; } function foo (arr) { Console.log (arr); if (IsArray (arr)) { For (i in arr) { (function (j) { settimeout (function () { Foo (arr[j]); }, 0); }) (i); } } } Foo ([[1, 2], [3, 4]]); /* Output: [[1,2],[3,4]] [1,2] [3,4] 1 2 3 4 */ There's a callback. function IsArray (o) { return tostring.apply (o) = = ' [Object Array] '; } Sets a counter that identifies the "number of known elements that have not been traversed" and the starting value is obviously 1 var cbcounter = 1; function foo (arr, CB) { Cbcounter + = IsArray (arr)? arr.length:0; The number of the handle element plus, because the child element is now Cicada Console.log (arr); if (IsArray (arr)) { For (i in arr) { (function (j) { settimeout (function () { Foo (Arr[j], CB); }, 0); }) (i); } } if ((--cbcounter = = 0) && (typeof cb = = ' function ')) CB (); The front--just dig yourself out. } Foo ([[1, 2], [3, 4]], function () { Console.log (' I am a callback! '); }); /* Output: [[1,2],[3,4]] [1,2] [3,4] 1 2 3 4 I am a callback! */