Predate / Postdate

Use the following table to calculate the date of any number of days from now, forwards or backwards.

   
Number of days PreDate
Show Time

<script type="text/javascript">
<!-- Predate / Postdate Script
//jeff
//www.huntingground.freeserve.co.uk

IE=document.all
function prePostDate(){

days=5 // for predates enter a negative number

showTime=0 //0 = no 1 = yes

if(days>0){
txt="In "+days+" days time it will be:" // postdate display
}
else{
temp= -days

if(temp==1){
txt= temp+" day ago it was "
}
else{
txt= temp+" days ago it was "
}

}

if(isNaN(days)){
days=0
}

var now = new Date();
now.setTime(now.getTime() + days * 24 * 60 * 60 * 1000)
timeValue=now.toString()

if(showTime==0){ // display date
text=txt
if(IE){timeValue=timeValue.substring(0,10)+timeValue.substring(timeValue.length,timeValue.length-5)}
else{timeValue=timeValue.substring(0,15)}
}
else{ // display date and time, single days date figure

if(timeValue.charAt(16)!=" "){
if(IE){timeValue=timeValue.substring(0,10)+timeValue.substring(timeValue.length,timeValue.length-5)+" "+timeValue.substring(10,19)}
else{timeValue=timeValue.substring(0,24)}

text=txt
}
else{ // display date and time, double days date figure
timeValue=timeValue.substring(0,10)+timeValue.substring(timeValue.length,timeValue.length-5)+timeValue.substring(10,19)
}
}


alert(text+"\n\n"+timeValue)

}
// -->
</script>

Calculate the date from start date in number of days

Start DateNumber of daysEnd Date

<script type="text/javascript">
<!--
function fromDate(s) {
days=(document.f2.daynums.value*1)//-1
var dateArray = s.split('/');
sdate = new Date(dateArray[2],dateArray[1]-1,dateArray[0]);
if(dateArray[2].length<4){
alert("Please Enter The Year As A Four Digit Number\n\nExample:- 2002\n\nThank You")
return document.f2.date_to.value=""
}
else{
var odate = new Date(sdate.getTime() + (days * 86400000));
return odate.getDate() + '/' + (odate.getMonth()+1) + '/' + odate.getYear();
}
}
//-->
</script>


<P>Calculate the date from start date in number of days.


<form name="f2">
<P><table border=1>
<tr><td>Start Date</td><td>Number of days</td><td>End Date</td></tr>
<tr><td><input type="text" name="date_from" size="10" value="25/09/2002"></td>
<td align="center"><input type="text" name="daynums" size="4" maxlength="4" value="5"></td>
<td><input type="text" name="date_to" size="10"></td></tr>
<tr><td colspan=3 align=center>
<input type="button" value="calculate" onclick="this.form.date_to.value=fromDate(this.form.date_from.value);">
</td></tr></table>
</form>

Calculate the days from start date to end date

Start DateEnd DateNumber of days

<script type="text/javascript">
<!--
function startEndDate() {
from=document.f3.date_from.value
to=document.f3.date_to.value

var fromArray = from.split('/');
fromdate = new Date( fromArray[2], fromArray[1]-1, fromArray[0]);

var toArray = to.split('/');
todate = new Date( toArray[2], toArray[1]-1, toArray[0]);

document.f3.daynums.value=(todate-fromdate)/86400000

}
//-->
</script>

<P>Calculate the days from start date to end date.

<P><form name="f3">
<P><table border=1>
<tr><td>Start Date</td><td>End Date</td><td>Number of days</td></tr>
<tr><td><input type="text" name="date_from" size="10" value="25/09/2002"></td>
<td><input type="text" name="date_to" size="10" value="26/09/2002"></td>
<td align="center"><input type="text" name="daynums" size="4" maxlength="4" value=""></td></tr>
<tr><td colspan=3 align=center>
<input type="button" value="calculate" onclick="startEndDate()">
</td></tr></table>
</form>