jQuery-将一个函数作为参数传递给另一个函数，每次调用一个函数时检查返回值

Question

I have a function that each time returns different value:

this.imageArr = [ "1.png", "2.png" ]

this.changeImg = function () {
    return $( "#Img" ).attr("src", "images/" + this.imageArr[Math.floor(Math.random()*this.imageArr.length)]);
}

This function each time it is called changes randomly src of image.

now, i have second function that manages multiple animation

$.fn.animationNSteps = function ( className, delay, steps, infinite, visibility, func ) {
      [...]
      $(this).animationNSteps( className, delay, steps, infinite, visibility, func )
}

Last parameter is "func". If it is given (it sometimes is given, sometimes is not) it should randomly change picture using previous function changeImg() . Unfortunately if I call it like this:

$("#title").animationNSteps ( class, 3000, 3, true, true, obj.changeImg )

It randomly takes picture for the first call, but next one and all the others are still the same. How to call changeImg() function each time to change the image?

Answer 1

Try this:

$("#title").animationNSteps ( 
    class, 3000, 3, true, true, 
    function(){
        return obj.changeImg();
    } )