https://archivepmo.nic.in/drmanmohansingh/js/swithcer.js

1//Style Sheet Switcher version 1.1 Oct 10th, 2006
2//Author: Dynamic Drive: http://www.dynamicdrive.com
3//Usage terms: http://www.dynamicdrive.com/notice.htm
4
5//Unofficial Update to fix Safari 5.1 glitch re: alternate stylesheets or the disabled property in regards to them
6// See: http://www.dynamicdrive.com/forums/showthread.php?p=259199 for more info
7
8var manual_or_random="manual" //"manual" or "random"
9var randomsetting="3 days" //"eachtime", "sessiononly", or "x days (replace x with desired integer)". Only applicable if mode is random.
10
11//////No need to edit beyond here//////////////
12
13function getCookie(Name) { 
14var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
15if (document.cookie.match(re)) //if cookie found
16return document.cookie.match(re)[0].split("=")[1] //return its value
17return null
18}
19
20function setCookie(name, value, days) {
21var expireDate = new Date()
22//set "expstring" to either future or past date, to set or delete cookie, respectively
23var expstring=(typeof days!="undefined")? expireDate.setDate(expireDate.getDate()+parseInt(days)) : expireDate.setDate(expireDate.getDate()-5)
24document.cookie = name+"="+value+"; expires="+expireDate.toGMTString()+"; path=/";
25}
26
27function deleteCookie(name){
28setCookie(name, "moot")
29}
30
31
32function setStylesheet(title, randomize){ //Main stylesheet switcher function. Second parameter if defined causes a random alternate stylesheet (including none) to be enabled
33var i, cacheobj, altsheets=[""];
34if(setStylesheet.chosen)
35try{
36document.getElementsByTagName('head')[0].removeChild(setStylesheet.chosen);
37}catch(e){}
38for(i=0; (cacheobj=document.getElementsByTagName("link")[i]); i++) {
39if(cacheobj.getAttribute("rel").toLowerCase()=="alternate stylesheet" && cacheobj.getAttribute("title")) { //if this is an alternate stylesheet with title
40cacheobj.disabled = true
41altsheets.push(cacheobj) //store reference to alt stylesheets inside array
42if(cacheobj.getAttribute("title") == title){ //enable alternate stylesheet with title that matches parameter
43cacheobj.disabled = false //enable chosen style sheet
44setStylesheet.chosen = document.createElement('link');//cloneNode(false);
45setStylesheet.chosen.rel = 'stylesheet';
46setStylesheet.chosen.type = 'text/css';
47if(cacheobj.media)
48setStylesheet.chosen.media = cacheobj.media;
49setStylesheet.chosen.href = cacheobj.href;
50document.getElementsByTagName('head')[0].appendChild(setStylesheet.chosen);
51}
52}
53}
54if (typeof randomize!="undefined"){ //if second paramter is defined, randomly enable an alt style sheet (includes non)
55var randomnumber=Math.floor(Math.random()*altsheets.length)
56altsheets[randomnumber].disabled=false
57}
58return (typeof randomize!="undefined" && altsheets[randomnumber]!="")? altsheets[randomnumber].getAttribute("title") : "" //if in "random" mode, return "title" of randomly enabled alt stylesheet
59}
60
61
62
63function chooseStyle(styletitle, days){ //Interface function to switch style sheets plus save "title" attr of selected stylesheet to cookie
64if (document.getElementById){
65setStylesheet(styletitle)
66setCookie("mysheet", styletitle, days)
67}
68}
69
70function indicateSelected(element){ //Optional function that shows which style sheet is currently selected within group of radio buttons or select menu
71if (selectedtitle!=null && (element.type==undefined || element.type=="select-one")){ //if element is a radio button or select menu
72var element=(element.type=="select-one") ? element.options : element
73for (var i=0; i<element.length; i++){
74if (element[i].value==selectedtitle){ //if match found between form element value and cookie value
75if (element[i].tagName=="OPTION") //if this is a select menu
76element[i].selected=true
77else{ //else if it's a radio button
78element[i].checked=true
79}
80break
81}
82}
83}
84}
85
86if (manual_or_random=="manual"){ //IF MANUAL MODE
87var selectedtitle=getCookie("mysheet")
88if (document.getElementById && selectedtitle!=null) //load user chosen style sheet from cookie if there is one stored
89setStylesheet(selectedtitle)
90}
91else if (manual_or_random=="random"){ //IF AUTO RANDOM MODE
92if (randomsetting=="eachtime")
93setStylesheet("", "random")
94else if (randomsetting=="sessiononly"){ //if "sessiononly" setting
95if (getCookie("mysheet_s")==null) //if "mysheet_s" session cookie is empty
96document.cookie="mysheet_s="+setStylesheet("", "random")+"; path=/" //activate random alt stylesheet while remembering its "title" value
97else
98setStylesheet(getCookie("mysheet_s")) //just activate random alt stylesheet stored in cookie
99}
100else if (randomsetting.search(/^[1-9]+ days/i)!=-1){ //if "x days" setting
101if (getCookie("mysheet_r")==null || parseInt(getCookie("mysheet_r_days"))!=parseInt(randomsetting)){ //if "mysheet_r" cookie is empty or admin has changed number of days to persist in "x days" variable
102setCookie("mysheet_r", setStylesheet("", "random"), parseInt(randomsetting)) //activate random alt stylesheet while remembering its "title" value
103setCookie("mysheet_r_days", randomsetting, parseInt(randomsetting)) //Also remember the number of days to persist per the "x days" variable
104}
105else
106setStylesheet(getCookie("mysheet_r")) //just activate random alt stylesheet stored in cookie
107} 
108}