How to add css class by default for all the images

Question

Adding css class to all the image elements is a lengthy task and I was wondering if we can add css class to all the images by default. Something like this:

img {class:'hover-share-buttons';}

but the technique doesn't seem to work. Is there something wrong with this code or am I doing it completely wrong? Normal css is easy to add but can we add an class ?

An answer will be much appreciated. I am trying this on weebly http://geniusknight.weebly.com. The class attribute comes from an external js file (addthis lab js) and sorry about putting the .img there, it was my bad but still it doesn't work. You see I have no css for that because the class attribute is coming from addthis script.

Answer 1

You could just use:

img {

    // Your styles for all images

}

However, if you want to add default class to all images, you need to use javascript:

var i, images = document.getElementsByTagName("img");

for(i = 0; i < images.length; i++) {
    images[i].className += " hover-share-buttons";
}

or easier if you're able to use jQuery:

$("img").addClass("hover-share-buttons");