problems comparing two dates

[CHRISWYA]

i am using the following javascript validation to ensure that a open date is greater than a close date. However i have just discovered that the .value check is not successfully working as it does not interpretate 01/10/04 as being greater than 28/09/04 for example. The check successfully occurs however for open/close dates from the same month.any suggestions please!?

if(theForm.p_close_date.value!=0)
{
if (theForm.p_open_date.value > theForm.p_close_date.value)
{
alert("The close date entered is invalid");
theForm.p_close_date.focus();
return false;
}
}
return true;
}
</script>

 

[BillyRayPreachersSon]

i have just discovered that the .value check is not successfully working as it does not interpretate 01/10/04 as being greater than 28/09/04

On the contrary - the value "check" and string comparison is working 100% - it is your logic and understanding that is not working ;o)

You are comparing a string with a string - which will not do any magic date checking. To do this, you have to convert the strings to a date object. You can either split the date up and pass the component DMY parts to a new date object yourself, or, (I believe) you can pass a formatted date string for it to parse.

Once you have your two date objects, comparing is a lot easier. You can call the getTime() method to return a number which you can use for comparison purposes (as the number bears a direct relationship to the date)... Something like this (once you have the date objects, of course):

if (open_date.getTime() > close_date.getTime()) {
   ...
}

Hope this helps,
Dan

 

[CHRISWYA]

Thanks for the advice i am very new to Javascript and dont quite follow all the advice given but thanks very much for you time.