ansaurus

Question

Use of setTimeout

Answer 1

A:

Your swap function requires a parameter, so it won't work with setTimeout.

OJ 2008-12-17 00:48:46

oh yeah lol :) that would do it actually :)

Strelok 2008-12-17 00:50:43

Answer 2

+2 A:

There are a couple of things wrong here. First, its passing code to be eval'ed in the first parameter of setTimeout is not recommended. Better pass a callback instead:

 setTimeout(function() { swap(); },10000);
 //Or
 setTimeout(swap,10000); //Passing the actual function as the callback

Second, you are calling the swap() method without parameters inside the timeout. It should pass in a new image filename (perhaps by declaring an array of filenames), or check whether the parameter is set or not.

function swap(newImage,element) { 
   if(newImage) {
       var fileName = newImage.toString()+".jpg"; 
       element.src = fileName;
   }
   t=setTimeout(this,10000) 
}

This function obviously won't do anything after the first run (since no new image filenames are supplied). Using an array you could iterate over several filenames:

var images = ['1.jpg','2.jpg','3.jpg'];
var slideshow = function(element, images, index) {
   if(!index || ( (index + 1) > images.length) ) index = 0;
   element.src = images[index];
   t = setTimeout(function(){
       slideshow(element, images, index + 1);
   },10000) 
};

//Fetch the image element the slideshow is running on
var element = document.slideshow; 
slideshow(element, images);

This will continue switching between the images in the array until the timeout is canceled.

Eran Galperin 2008-12-17 00:58:45

setTimeout can accept a string as the first parameter. that string gets eval()'d so his method would work, if not for forgetting to pass the parameter.

nickf 2008-12-17 01:17:28

You are right, though it is not recommended. Edited

Eran Galperin 2008-12-17 01:24:22

Answer 3

A:

Javascript isn't necessary to do a slideshow. All you have to do is put each image into a separate page, then add this single line to the top of each page in the <head> section:

<meta http-equiv="refresh" content="10;url=NextPage.html"/>

"10" is the number of seconds to wait before going to the next page, and "NextPage.html" is the link to the page containing the next image to display.

Mark Ransom 2008-12-17 05:14:14

ansaurus

tags:

views:

answers:

Use of setTimeout

related questions