JavaScript – Calendar – Date Picker

<!DOCTYPE html>
<html>
<head>

<style type="text/css">
span.label {color:black;width:30;height:16;text-align:center;margin-top:0;background:#ffF;font:bold 13px Arial}
span.c1 {cursor:hand;color:black;width:30;height:16;text-align:center;margin-top:0;background:#ffF;font:bold 13px Arial}
span.c2 {cursor:hand;color:red;width:30;height:16;text-align:center;margin-top:0;background:#ffF;font:bold 13px Arial}
span.c3 {cursor:hand;color:#b0b0b0;width:30;height:16;text-align:center;margin-top:0;background:#ffF;font:bold 12px Arial}
</style>

<script type="text/javascript">
function maxDays(mm, yyyy){
var mDay;
	if((mm == 3) || (mm == 5) || (mm == 8) || (mm == 10)){
		mDay = 30;
  	}
  	else{
  		mDay = 31
  		if(mm == 1){
   			if (yyyy/4 - parseInt(yyyy/4) != 0){
   				mDay = 28
   			}
		   	else{
   				mDay = 29
  			}
		}
  }
return mDay;
}
function changeBg(id){
	if (eval(id).style.backgroundColor != "yellow"){
		eval(id).style.backgroundColor = "yellow"
	}
	else{
		eval(id).style.backgroundColor = "#ffffff"
	}
}
function writeCalendar(){
var now = new Date
var dd = now.getDate()
var mm = now.getMonth()
var dow = now.getDay()
var yyyy = now.getFullYear()
var arrM = new Array("January","February","March","April","May","June","July","August","September","October","November","December")
var arrY = new Array()
	for (ii=0;ii<=4;ii++){
		arrY[ii] = yyyy - 2 + ii
	}
var arrD = new Array("Sun","Mon","Tue","Wed","Thu","Fri","Sat")

var text = ""
text = "<form name=calForm>"
text += "<table border=1>"
text += "<tr><td>"
text += "<table width=100%><tr>"
text += "<td align=left>"
text += "<select name=selMonth onChange='changeCal()'>"
	for (ii=0;ii<=11;ii++){
		if (ii==mm){
			text += "<option value= " + ii + " Selected>" + arrM[ii] + "</option>"
		}
		else{
			text += "<option value= " + ii + ">" + arrM[ii] + "</option>"
		}
	}
text += "</select>"
text += "</td>"
text += "<td align=right>"
text += "<select name=selYear onChange='changeCal()'>"
	for (ii=0;ii<=4;ii++){
		if (ii==2){
			text += "<option value= " + arrY[ii] + " Selected>" + arrY[ii] + "</option>"
		}
		else{
			text += "<option value= " + arrY[ii] + ">" + arrY[ii] + "</option>"
		}
	}
text += "</select>"
text += "</td>"
text += "</tr></table>"
text += "</td></tr>"
text += "<tr><td>"
text += "<table border=1>"
text += "<tr>"
	for (ii=0;ii<=6;ii++){
		text += "<td align=center><span class=label>" + arrD[ii] + "</span></td>"
	}
text += "</tr>"
aa = 0
	for (kk=0;kk<=5;kk++){
		text += "<tr>"
		for (ii=0;ii<=6;ii++){
			text += "<td align=center><span id=sp" + aa + " onClick='changeBg(this.id)'>1</span></td>"
			aa += 1
		}
		text += "</tr>"
	}
text += "</table>"
text += "</td></tr>"
text += "</table>"
text += "</form>"
document.write(text)
changeCal()
}
function changeCal(){
var now = new Date
var dd = now.getDate()
var mm = now.getMonth()
var dow = now.getDay()
var yyyy = now.getFullYear()
var currM = parseInt(document.calForm.selMonth.value)
var prevM
	if (currM!=0){
		prevM = currM - 1
	}
	else{
		prevM = 11
	}
var currY = parseInt(document.calForm.selYear.value)
var mmyyyy = new Date()
mmyyyy.setFullYear(currY)
mmyyyy.setMonth(currM)
mmyyyy.setDate(1)
var day1 = mmyyyy.getDay()
	if (day1 == 0){
		day1 = 7
	}
var arrN = new Array(41)
var aa
	for (ii=0;ii<day1;ii++){
		arrN[ii] = maxDays((prevM),currY) - day1 + ii + 1
	}
	aa = 1
	for (ii=day1;ii<=day1+maxDays(currM,currY)-1;ii++){
		arrN[ii] = aa
		aa += 1
	}
	aa = 1
	for (ii=day1+maxDays(currM,currY);ii<=41;ii++){
		arrN[ii] = aa
		aa += 1
	}
	for (ii=0;ii<=41;ii++){
		eval("sp"+ii).style.backgroundColor = "#FFFFFF"
	}
var dCount = 0
	for (ii=0;ii<=41;ii++){
		if (((ii<7)&&(arrN[ii]>20))||((ii>27)&&(arrN[ii]<20))){
			eval("sp"+ii).innerHTML = arrN[ii]
			eval("sp"+ii).className = "c3"
		}
		else{
			eval("sp"+ii).innerHTML = arrN[ii]
			if ((dCount==0)||(dCount==6)){
				eval("sp"+ii).className = "c2"
			}
			else{
				eval("sp"+ii).className = "c1"
			}
			if ((arrN[ii]==dd)&&(mm==currM)&&(yyyy==currY)){
				eval("sp"+ii).style.backgroundColor="#90EE90"
			}
		}
	dCount += 1
		if (dCount>6){
			dCount=0
		}
	}
}
</script>

</head>
<body>
<script type="text/javascript">writeCalendar()</script>
</body>
</html>

Notice the code ready to copy and paste:

<style type="text/css">
....
</style>

<script>
....
</script>

Notice:

<script type="text/javascript">writeCalendar()</script>

Put the code above in the body of your document, where you want the calendar to show up.

DEMO

 

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