29

I have two dates in javascript:

var first = '2012-11-21'; var second = '2012-11-03'; 

i would like make:

 if(first > second){ //... } 

how is the best way for this, without external library?

1
  • 3
    not a possible duplicate, an exact duplicate - even the titles are the same :) (Do people ever Google before asking questions?) Commented Jun 23, 2012 at 14:00

7 Answers 7

61
if( (new Date(first).getTime() > new Date(second).getTime())) { ---------------------------------- } 
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3 Comments

too much work, 2 new Date object, and 3 times multiplication, and compare it.
It's not working on dd/mm/yyyy format, So it need to convert to either mm/dd/yyyy or yyyy/mm/dd
It will work without calling getTime() method.
17

If your dates are strings in a strict yyyy-mm-dd format as shown in the question then your code will work as is without converting to date objects or numbers:

if(first > second){ 

...will do a lexographic (i.e., alphanumeric "dictionary order") string comparison - which will compare the first characters of each string, then the second characters of each string, etc. Which will give the result you want...

Comments

9

You can do this way, it will work fine:

var date1 = new Date('2013-07-30'); var date2 = new Date('2013-07-30'); if(date1 === date2){ console.log("both are equal");} //it does not work ==>undefined //result if(+date1 === +date2){ console.log("both are equal");} //do it this way! //(use + prefix for a variable that holds a date value) ==> both are equal //result 

Note :- don't forget to use a + prefix

Comments

5

The best way is,

var first = '2012-11-21'; var second = '2012-11-03'; if (new Date(first) > new Date(second) { ..... } 

Comments

4

Because of your date format, you can use this code:

if(parseInt(first.replace(/-/g,""),10) > parseInt(second.replace(/-/g,""),10)){ //... } 

It will check whether 20121121 number is bigger than 20121103 or not.

1 Comment

If that date format can be counted on then (as per my answer) you can just compare them as strings, no conversion necessary...
2

USe this function for date comparison in javascript:

 function fn_DateCompare(DateA, DateB) { var a = new Date(DateA); var b = new Date(DateB); var msDateA = Date.UTC(a.getFullYear(), a.getMonth()+1, a.getDate()); var msDateB = Date.UTC(b.getFullYear(), b.getMonth()+1, b.getDate()); if (parseFloat(msDateA) < parseFloat(msDateB)) return -1; // less than else if (parseFloat(msDateA) == parseFloat(msDateB)) return 0; // equal else if (parseFloat(msDateA) > parseFloat(msDateB)) return 1; // greater than else return null; // error } 

Comments

0

you can done this way also.

if (dateFormat(first, "yyyy-mm-dd") > dateFormat(second, "yyyy-mm-dd")) { console.log("done"); } 

OR

if (dateFormat(first, "mm-dd-yyyy") > dateFormat(second, "mm-dd-yyyy")) { console.log("done"); } 

i use following plugin for dateFormat()

 var dateFormat = function () { var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g, timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g, timezoneClip = /[^-+\dA-Z]/g, pad = function (val, len) { val = String(val); len = len || 2; while (val.length < len) val = "0" + val; return val; }; // Regexes and supporting functions are cached through closure return function (date, mask, utc) { var dF = dateFormat; // You can't provide utc if you skip other args (use the "UTC:" mask prefix) if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/\d/.test(date)) { mask = date; date = undefined; } // Passing date through Date applies Date.parse, if necessary date = date ? new Date(date) : new Date; if (isNaN(date)) throw SyntaxError("invalid date"); mask = String(dF.masks[mask] || mask || dF.masks["default"]); // Allow setting the utc argument via the mask if (mask.slice(0, 4) == "UTC:") { mask = mask.slice(4); utc = true; } var _ = utc ? "getUTC" : "get", d = date[_ + "Date"](), D = date[_ + "Day"](), m = date[_ + "Month"](), y = date[_ + "FullYear"](), H = date[_ + "Hours"](), M = date[_ + "Minutes"](), s = date[_ + "Seconds"](), L = date[_ + "Milliseconds"](), o = utc ? 0 : date.getTimezoneOffset(), flags = { d: d, dd: pad(d), ddd: dF.i18n.dayNames[D], dddd: dF.i18n.dayNames[D + 7], m: m + 1, mm: pad(m + 1), mmm: dF.i18n.monthNames[m], mmmm: dF.i18n.monthNames[m + 12], yy: String(y).slice(2), yyyy: y, h: H % 12 || 12, hh: pad(H % 12 || 12), H: H, HH: pad(H), M: M, MM: pad(M), s: s, ss: pad(s), l: pad(L, 3), L: pad(L > 99 ? Math.round(L / 10) : L), t: H < 12 ? "a" : "p", tt: H < 12 ? "am" : "pm", T: H < 12 ? "A" : "P", TT: H < 12 ? "AM" : "PM", Z: utc ? "UTC" : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""), o: (o > 0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4), S: ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10] }; return mask.replace(token, function ($0) { return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1); }); }; }(); // Some common format strings dateFormat.masks = { "default": "ddd mmm dd yyyy HH:MM:ss", shortDate: "m/d/yy", mediumDate: "mmm d, yyyy", longDate: "mmmm d, yyyy", fullDate: "dddd, mmmm d, yyyy", shortTime: "h:MM TT", mediumTime: "h:MM:ss TT", longTime: "h:MM:ss TT Z", isoDate: "yyyy-mm-dd", isoTime: "HH:MM:ss", isoDateTime: "yyyy-mm-dd'T'HH:MM:ss", isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'" }; // Internationalization strings dateFormat.i18n = { dayNames: [ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" ], monthNames: [ "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" ] }; // For convenience... Date.prototype.format = function (mask, utc) { return dateFormat(this, mask, utc); }; 

2 Comments

What is the dateFormat() function?
@nnnnnn i add one plugin for dateFormat().

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