Scan DOM attribute changes changes

dom-scanner.js

var scan = (function(attributes){
    var hashes = {},
        counter = 100000,
        CUSTOM_ID_ATTR = 'custom-id-attr-' + (Math.random() * 10000)

    function scan(root) {
        // if no root element provided then use the body element
        root = root ? root : document.getElementsByTagName('body')[0]

        var all = root.getElementsByTagName("*"),
            diff = [],
            keys = Object.keys(all)

        keys.forEach(function(key) {
            var n = all[key],
                customId = n.getAttribute(CUSTOM_ID_ATTR),
                tmp = ''

            attributes.forEach(function(att, i) {
                var val = n.getAttribute(att)
                tmp += val ? (att + ':' + val) : (att + ':')
                if(attributes.length - 1 > i)
                    tmp += '|'
            })

            if(!customId) {
                // new element
                customId = counter++
                n.setAttribute(CUSTOM_ID_ATTR, customId)
                hashes[customId] = tmp
                diff.push({ element: n, oldHash: null, newHash: tmp })
            }
            else {
                if(hashes[customId] != tmp) {
                    var differences = ''
                    var oldHash = hashes[customId].split('|')
                    var newHash = tmp.split('|')

                    for(var x = 0; x < attributes.length; x++) {
                        if(oldHash[x] != newHash[x])
                            differences += newHash[x] + '|'
                    }

                    var index = differences.lastIndexOf('|')

                    if(index === differences.length-1)
                        differences = differences.substring(0, index)

                    diff.push({ element: n, oldHash: hashes[customId], newHash: tmp, diff: differences})
                    hashes[customId] = tmp
                }
            }

        })

        return diff
    }

    scan()
    return scan
})(['class', 'style', 'id'])