xhr.onreadystatechange = function(e) {
    if ( 4 == this.readyState && 200 == this.status ) {
        // PHP returns "result~~<File Uploaded OK>~~n"
        response = xhr.responseText.split(">~~n");
        var xhrData = {};
        for(j=0;j<response.length-1;j++) {
            splt = response[j].split("~~<");
            key = splt[0];
            data = splt[1];
            xhrData[key] = data;
        }
        for(key in xhrData) {
            console.log("Key: "+key+"nData: "+xhrData[key]);
           //Key: result
           //Data: File Uploaded OK
        }
        console.log(xhrData.result);      //undefined
        console.log(xhrData['result']);   //undefined
    }
};