Stackoverflow answer about math.random

// ==UserScript==
// @name         Predict color CSGOPolygon
// @namespace
// @version      0.5
// @author       RESTRITOn
// @match        http://csgopolygon.com/*
// @grant        none
// ==/UserScript==
var num="";

var connect="ws://csgopolygon.com:8080";

function zmien_num(){
    connect;
    var letter = ['1','2','3','4','5','6','7','8','9'];
    var pattern = letter[Math.floor(Math.random() * letter.length)];
    var ball = 'ball-'; // hexadecimal starting symbol
    var letter2=[''];
    if (pattern == "1"){
        letter2 = ['0'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "2"){
        letter2 = ['1','1','8','8'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "3"){
        letter2 = ['8','8','1','1'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "4"){
        letter2 = ['8','1'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "5"){
        letter2 = ['1','8'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "6"){
        letter2 = ['1','1','8'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "7"){
        letter2 = ['8','8','1'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "8"){
        letter2 = ['1'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }

    if (pattern == "9"){
        letter2 = ['8'];
        ball += letter2[Math.floor(Math.random() * letter2.length)];
        num='<b class="ball '+ball+'"></b>';
    }
}
zmien_num();

setInterval(function(){if($("#banner").text() == "***ROLLING***"){zmien_num();}}, 100);

setInterval(function(){
    var letters = "0123456789ABCDEF";
    color = '#';
    for( var i=0; i < 6; i++ ) {
        color += letters.charAt(Math.floor(Math.random() * letters.length));
    }
    $("#rollscript").html(num);

    $("#setcolor3").html('<span style="font-size: 21px; color: '+color+'"><b>?</b></span>');
    $(".bootbox-body").css({"font-size": "4%"});
    $( "#pullout" ).hide();
    $("#setcolor4").html('<span style="font-size: 21px; color: '+color+'"><b>DONATE</b></span>');
    $("#setcolor5").html('<span style="font-size: 21px; color: '+color+'"><b>?</b></span>');
}, 250);