function getAttrFromString(str, node, attr) {
    var regex = new RegExp('<' + node + ' .*?' + attr + '="(.*?)"', "gi"), result, res = [];
    while ((result = regex.exec(str))) {
        res.push(result[1]);
    }
    return res;
}

var arrayOfImageSrcs = getAttrFromString(
  '<img src="http://placekitten.com/350/300"><img src="http://placekitten.com/350/300">',
  'img',
  'src'
);