//----------- serializing/deserializing procedures

    //encoding int contours array to be sent as base64 string
    function getBase64IntArray(arr) {

        var width = arr.length;
        //This works given the inner arrays length never changes.
        var height = arr[0].length;
        //string that would contain data
        var str = width.toString()+","+height.toString()+",";

        for(var x = 0; x < height; x++) {
            for(var y = 0; y < width; y++) {
               str = str + arr[x][y].toString() + ",";
            }
        }

        var str64 = btoa(str);
        return str64;
    }//getBase64IntArray

    //deconding this string back to array
    function getIntArrayfromBase64(str64) {

        var str = atob(str64);
        //first occurence of ","
        var width_str = str.substr(0,str.indexOf(','));
        str = str.substr(str.indexOf(',')+1); // cut the beginning
        //again first occurence of ","
        var height_str = str.substr(0,str.indexOf(','));
        str = str.substr(str.indexOf(',')+1); // cut the beginning

        var width = parseInt(width_str);
        var height = parseInt(height_str);

        //declare new array and fill it
        var arr = new Array(height);
        var curr_str = "";

        for(var x = 0; x < height; x++) {

            arr[x] = new Array(width);

            for(var y = 0; y < width; y++) {
               //first occurence of ","
               curr_str = str.substr(0,str.indexOf(','));
               // cut the beginning
               str = str.substr(str.indexOf(',')+1);
               arr[x][y]=parseInt(curr_str);
            }
        }

        return arr;

    }// getIntArrayfromBase64

//----------- example usage
    function send(){
    //encoding to base64
    var arr = [
          [1, 2],
          [3, 4]
    ];

    var base64 = getBase64IntArray(arr);
    webSocket.send(base64);
    }

    webSocket.onmessage = function(event){

    //reading array as base64 string
    var arr = getIntArrayfromBase64(event.data);
    var width = arr.length;
    var height = arr[0].length;

    writeResponse("Received "+width+" "+height+" "+arr[0][0]+arr[1][1]);
    };