How to Compare Two Dates In JavaScript

Introduction

I have encountered many confused developers attempting to compare two dates in JavaScript. There are many methods or algorithms for comparing dates in JavaScript, but I will explain the simplest ways to compare dates and times using JavaScript.

This article will help you to resolve the following problems,

1. Compare two dates with time.
2. Compare today's date with any other date.
3. Compare past and future dates with a given date.

Create a Date Object in JavaScript

The following describes the creation of Date objects,

1. First, we need to create a date object.
2. The Date object is used to work with dates and times.
3. Date objects are created with the Date() constructor.
4. There are four ways of instantiating a date object:
   • new Date() //This will return the current date and time.
   • new Date(milliseconds)
   • new Date(dateString)
   • new Date(year, month, day, hours, minutes, seconds, milliseconds)
5. Here are a few examples of instantiating a date,
   • var today = new Date() //Current date
   • var anotherDate = new Date("March 01, 2000 20:50:10")
   • var anotherDate = new Date(2000,03,01)
   • var anotherDate = new Date(2000,03,01,20,50,10)
6. Note. Here, the month parameter will start from 0 to 11.

Comparing dates in JavaScript

The following describes how to compare the two dates,

1. I have two dates. Date one is 15-01-2010, and another date is 15-01-2011.
2. I compare these two dates using the following JavaScript code.

<script type="text/javascript"language="javascript">    
       function CompareDate() {    
           //Note: 00 is month i.e. January    
           var dateOne = new Date(2010, 00, 15); //Year, Month, Date    
           var dateTwo = new Date(2011, 00, 15); //Year, Month, Date    
           if (dateOne > dateTwo) {    
                alert("Date One is greater than Date Two.");    
            }else {    
                alert("Date Two is greater than Date One.");    
            }    
        }    
        CompareDate();    
</script> 

Output

Comparing dates with time in JavaScript

The following describes how to compare dates with times:

1. Here I will compare two dates with their times.
2. I have two dates
   - Date One: 20-05-2012 14:55:59
   - Date Two: 20-05-2012 12:10:20
3. The following JavaScript code will compare these dates with their times.

<script type="text/javascript"language="javascript">    
       function CompareDate() {    
           //            new Date(Year, Month, Date, Hr, Min, Sec);    
           var dateOne = new Date(2012, 04, 20, 14, 55, 59);    
           var dateTwo = new Date(2012, 04, 20, 12, 10, 20);    
            //Note: 04 is month i.e. May    
           if (dateOne > dateTwo) {    
                alert("Date One is greater than Date Two.");    
            }else {    
                alert("Date Two is greater than Date One.");    
            }    
        }    
        CompareDate();    
</script>   

Output

Comparing today's date with another date

The following describes how to compare today's date with another date,

1. The following code will compare today's date with the given date.
2. The given date is 25-12-2010. This date will be compared with today's date using the following code,

   <script type="text/javascript"language="javascript">    
          function CompareDate() {    
              var todayDate = new Date(); //Today Date    
              var dateOne = new Date(2010, 11, 25);    
              if (todayDate > dateOne) {    
                   alert("Today Date is greater than Date One.");    
               }else {    
                   alert("Today Date is greater than Date One.");    
               }    
           }    
           CompareDate();    
   </script> 

Output

Some valuable methods of Date Objects,

• getDate- Returns the day of the month (1-31) for the specified date according to local time.
• getDay- Returns the day of the week (0-6) for the specified date according to local time.
• getFullYear- Returns the year (4 digits for 4-digit years) of the specified date according to local time.
• getHours- Returns the hour (0-23) on the specified date according to local time.
• getMilliseconds- Returns the milliseconds (0-999) in the specified date according to local time.
• getMinutes- Returns the minutes (0-59) on the specified date according to local time.
• getMonth- Returns the month (0-11) on the specified date according to local time.
• getSeconds- Returns the seconds (0-59) in the specified date according to local time.
• getTime- Returns the numeric value of the specified date as the number of milliseconds since January 1, 1970, 00:00:00 UTC (negative for prior times).
• getTimezoneOffset- Returns the time-zone offset in minutes for the current locale.
• getUTCDate- Returns the day (date) of the month (1-31) on the specified date according to universal time.
• getUTCDay- Returns the day of the week (0-6) on the specified date according to universal time.
• getUTCFullYear- Returns the year (4 digits for 4-digit years) in the specified date according to universal time.
• getUTCHours- Returns the hours (0-23) on the specified date according to universal time.
• getUTCMilliseconds- Returns the milliseconds (0-999) in the specified date according to universal time.
• getUTCMinutes- Returns the minutes (0-59) in the specified date according to universal time.
• getUTCMonth- Returns the month (0-11) on the specified date according to universal time.
• getUTCSeconds- Returns the seconds (0-59) in the specified date according to universal time.
• getYear- Returns the year (usually 2-3 digits) on the specified date according to local time. Use getFullYear instead.
• setDate- Sets the day of the month (1-31) for a specified date according to local time.
• setFullYear- Sets the entire year (4 digits for 4-digit years) for a specified date according to local time.
• setHours- Sets the hours (0-23) for a specified date according to local time.
• setMilliseconds- Sets the milliseconds (0-999) for a specified date according to local time.
• setMinutes- Sets the minutes (0-59) for a specified date according to local time.
• setMonth- Sets the month (0-11) for a specified date according to local time.
• setSeconds- Sets the seconds (0-59) for a specified date according to local time.
• setTime- Sets the Date object to the time represented by several milliseconds since January 1, 1970, 00:00:00 UTC, allowing for negative numbers for times prior.
• setUTCDate- Sets the day of the month (1-31) for a specified date according to universal time.
• setUTCFullYear- Sets the entire year (4 digits for 4-digit years) for a specified date according to universal time.
• setUTCHours- Sets the hour (0-23) for a specified date according to universal time.
• setUTCMilliseconds- Sets the milliseconds (0-999) for a specified date according to universal time.
• setUTCMinutes- Sets the minutes (0-59) for a specified date according to universal time.
• setUTCMonth- Sets the month (0-11) for a specified date according to universal time.
• setUTCSeconds- Sets the seconds (0-59) for a specified date according to universal time.
• setYear- Sets the year (usually 2-3 digits) for a specified date according to local time. Use setFullYear instead.
• toDateString- Returns the "date" portion of the Date as a human-readable string.

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