jquery setTimeout inside each

问题

i have some code similar to this, that moves inside some images... it works but it doesn't seem to respect timer

var i = 1;
var indexArray = array(1,2,3);
var timerx = new Array();

$( indexArray ).each(function( indexArraykey ) {

    function internalCallback ( i, indexArraykey ) {
        val = indexArray[indexArraykey];
        console.log("test " + i + val);
    }); 

    timerx[i] = setTimeout( internalCallback( i, indexArraykey ), i * 500000 );                     

    i++;

}); 

回答1:

A few points :

• i has the value of end of loop by the time the callback is called.
• to iterate over an array using jQuery, use $.each(array,, not $(array).each(
• the function doesn't have to be defined in the loop
• each gives the index as second argument of the callback and as first argument the value.

So it seems that what you want is in fact this :

var indexArray = array(1,2,3);
var timerx = [];
$.each(indexArray, function( indexArrayValue, i ) {
    timerx.push(setTimeout(function(){
        console.log("test " + i + ' : ' + indexArrayValue);
    }, (i+1) * 500000));
}); 

回答2:

That is so poor design, no but a total anti js pattern even beyond... Why would you define the same function over and over again!!!

$(imgNumArray).each(function (indexArraykey) {
    (function (i) {
        timerx[i] = setTimeout(internalCallback(i, indexArraykey), i * 500000);
    })(i++);
});

function internalCallback(i, indexArraykey) {
    val = indexArray[indexArraykey];
    console.log("test " + i + val);
}

回答3:

I am not javascript expert, but looks like here internalCallback is getting called instead of being passed as function to setTimeout.

Try this:

var i = 1;
var indexArray = [3,6,9];
var timerx = new Array();

$( indexArray ).each(function( indexArraykey ) {

    function internalCallback ( i, indexArraykey ) {
        return function () {
            val = indexArray[indexArraykey];
            console.log("test " + i + val);
        }
    } 

    timerx[i] = setTimeout( internalCallback( i, indexArraykey ), i * 5000);                     

    i++;

}); 

here is the fiddle http://jsfiddle.net/Guxdz/2/ (check the console log)

来源：https://stackoverflow.com/questions/15573859/jquery-settimeout-inside-each