Load image... when time is eating up

here is a sameple code, I would l开发者_JAVA百科ike to know when the browser is REALLY loading image

when you assign an image path to a array like that

imageNames[0] = 'image1.jpg';

or when you make

myImage = new Image();
myImage.src = imageNames[0];

i have put some timer.. but did not get concluant result ! HELP

---

You would look at the load event. Attach it with the ancient onload or addEventListener()/attachEvent() depending on your browser support requirements.

myImage = new Image;

myImage.onload = function() {
   alert('Image loaded');
}

myImage.src = imageNames[0];

jsFiddle.

You could also check if the image is already loaded by checking the complete property.

---

The key thing to note is that just because a human being can see that something could be a resource identifier / locator, the computer cannot.

When you assign a string to a point in an array:

imageNames[0] = 'image1.jpg';

the fact that 'image1.jpg' is a licit path to an image on your.host.net is not something the browser can determine on its own - the browser cannot recognize that the string 'image1.jpg' is a resource representation rather than a resource itself.

Once you set a DOM image's src property to be the string 'image1.jpg' the browser can recognize the string should be treated as a resource identifier (because the DOM element you created is an image, and the image's src property is supposed to be a URI pointing at an image resource which can be accessed and downloaded) and the browser will try and acquire that resource through means of its own.

---

The browser downloads the image when you assign a URL to the src attribute of an img element. Try this in the console of your browser and watch the Network tab:

var img = document.createElement('img');
img.src = 'foo';

You'll see network activity as soon as that second line executes.

It most certainly does nothing for imageNames[0] = 'image1.jpg'; since a string in an array could be anything, there's no way the browser has any idea this is supposed to be the URL of an image.