MediaWiki:Common.js

var button = {
        "imageFile": "images/citation.jpg",  //image to be shown on the button (may be a full URL too), 22x22 pixels
        "speedTip": "bloc de citation",    //text shown in a tooltip when hovering the mouse over the button
        "tagOpen": "<blockquote>",        //the text to use to mark the beginning of the block
        "tagClose": "</blockquote>",      //the text to use to mark the end of the block (if any)
        "sampleText": "bloc de citation"   //the sample text to place inside the block
};
mwCustomEditButtons.push(button);