Why JavaScript getTime() is not a function?

Question

I used the following function:

function datediff() {   var dat1 = document.getElementById('date1').value;   alert(dat1);//i get 2010-04-01   var dat2 = document.getElementById('date2').value;   alert(dat2);// i get 2010-04-13     var oneDay = 24*60*60*1000;   // hours*minutes*seconds*milliseconds   var diffDays = Math.abs((dat1.getTime() - dat2.getTime())/(oneDay));   alert(diffDays); } 

I get the error:

dat1.getTime()` is not a function 

Answer 1

That's because your dat1 and dat2 variables are just strings.

You should parse them to get a Date object, for that format I always use the following function:

// parse a date in yyyy-mm-dd format function parseDate(input) {   var parts = input.match(/(\d+)/g);   // new Date(year, month [, date [, hours[, minutes[, seconds[, ms]]]]])   return new Date(parts[0], parts[1]-1, parts[2]); // months are 0-based } 

I use this function because the Date.parse(string) (or new Date(string)) method is implementation dependent, and the yyyy-MM-dd format will work on modern browser but not on IE, so I prefer doing it manually.