Firstly please use forum tags to wrap your code...
Secondly, you can cut down on the amount of code you need by doing the following, take this
var images = []
images [1] = "images/green.png";
images [2] = "images/black.png";
images [3] = "images/green.png";
images [4] = "images/black.png";
images [5] = "images/green.png";
images [6] = "images/black.png";
images [7] = "images/green.png";
images [8] = "images/black.png";
images [9] = "images/green.png";
images [10] = "images/black.png";
images [11] = "images/green.png";
images [12] = "images/black.png";
images [13] = "images/green.png";
images [14] = "images/black.png";
images [15] = "images/green.png";
images [16] = "images/black.png";
images [17] = "images/green.png";
images [18] = "images/black.png";
images [19] = "images/green.png";
images [20] = "images/black.png";
images [21] = "images/green.png";
images [22] = "images/black.png";
images [23] = "images/green.png";
images [24] = "images/black.png";
images [25] = "images/green.png";
images [26] = "images/black.png";
images [27] = "images/green.png";
images [28] = "images/black.png";
images [29] = "images/green.png";
images [30] = "images/black.png";
images [31] = "images/green.png";
images [32] = "images/black.png";
images [33] = "images/green.png";
images [34] = "images/black.png";
images [35] = "images/green.png";
images [36] = "images/black.png";
images [37] = "images/green.png";
images [38] = "images/black.png";
images [39] = "images/green.png";
images [40] = "images/black.png";
images [41] = "images/green.png";
images [42] = "images/black.png";
images [43] = "images/green.png";
images [44] = "images/black.png";
images [45] = "images/green.png";
images [46] = "images/black.png";
images [47] = "images/green.png";
images [48] = "images/black.png";
images [49] = "images/green.png";
images [50] = "images/black.png";
images [51] = "images/green.png";
images [52] = "images/black.png";
images [53] = "images/green.png";
and do this with it
var images = ["",
"green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png","black.png","green.png"];
by compressing everything you need in to the array, noting the "", to occupy array element 0, you can save yourself space making code more readable
Now this
Date.prototype.getWeek = function() {
var onejan = new Date(this.getFullYear(),0,1); // month 0 is January
addDays(2);
return Math.ceil((((this - onejan) / 86400000) + onejan.getDay()+1)/7);
}
var today = new Date();
var weekno = today.getWeek();
in to
/* For a given date, get the ISO week number
*
* Based on information at:
*
* http://www.merlyn.demon.co.uk/weekcalc.htm#WNR
*
* Algorithm is to find nearest thursday, it's year
* is the year of the week number. Then get weeks
* between that date and the first day of that year.
*
* Note that dates in one year can be weeks of previous
* or next year, overlap is up to 3 days.
*
* e.g. 2014/12/29 is Monday in week 1 of 2015
* 2012/1/1 is Sunday in week 52 of 2011
*/
function getWeekNumber(d) {
// Copy date so don't modify original
d = new Date(d);
d.setHours(0,0,0);
// Set to nearest Thursday: current date + 4 - current day number
// Make Sunday's day number 7
d.setDate(d.getDate() + 4 - (d.getDay()||7));
// Get first day of year
var yearStart = new Date(d.getFullYear(),0,1);
// Calculate full weeks to nearest Thursday
var weekNo = Math.ceil(( ( (d - yearStart) / 86400000) + 1)/7)
// Return array of year and week number
return [d.getFullYear(), weekNo];
}
so modifying the above function c/o stackoverflow you get.
/* For a given date, get the ISO week number
* Based on information at:
* http://www.merlyn.demon.co.uk/weekcalc.htm#WNR
*/
function getWeekNumber(d) {
d = new Date(d);
d.setHours(0,0,0);
d.setDate(d.getDate() + 4 - (d.getDay()||7));
var yearStart = new Date(d.getFullYear(),0,1);
var weekNo = Math.ceil(( ( (d - yearStart) / 86400000) + 1)/7)
return weekNo;
}
weekno = getWeekNumber( new Date().toDateString() );
document.getElementById("myimage").src = "images/" + images[weekno];
I don't get what the purpose of window.location = 'week'+((new Date().getWeek()+1)%2)+'.png'; is for, so its left out.