Question

var img=new Image();
img.src='xxxxx';

Will the browser wait for the image to load then execute the next code line?

Answer 1

That action is asynchronous; a lot of image ‘pre-loading’ code relies on that feature.

EDIT: To give a little bit more useful information as well. If you’re wanting to have certain actions synchronously wait for images to load via javascript’s image object, you can use the onload event, like so:

var img = new Image();
img.onload = function () { /* onLoad code here */ };
img.src = 'xxxxxx';