如何在Javascript中检查月/年是否大于当前月/年

Question

I want to check if 08/2014 is greater than 02/2014..

How can I do that in Javascript?? Could someone help me please...

Currently I only check for future year. Here is the code snippet.

this.isDateGreaterThanCurrent=function(b){
    return parseInt(b)>parseInt(new Date().getFullYear());
};

Answer 1

With moment.js (which I recommend), then ..

var d1 = moment("08/2014", "MM/YYYY")
var d2 = moment("02/2014", "MM/YYYY")
d1.isBefore(d2) // false
d1.isAfter(d2)  // true

However, this can be done by hand without much effort.

Create a function that took in "MM/YYYY" and returns "YYYY-MM". The result can then be compared with a standard string compare. The major-first component layout is one reason why a format like ISO 8601 is nice - even as a string, it can be easily ordered.

function toPartialIso(str) {
    var m = str.match(/(\d{2})\/(\d{4})/);
    if (m) {
        return m[2] + "-" + m[1]
    }
    throw "bad date!"
}

toPartialIso("08/2014") < toPartialIso("02/2014")  // false
toPartialIso("08/2014") > toPartialIso("02/2014")  // true

Answer 2

construct two date object with

new Date(year, month)  //month start from 0 (ie january is 0)

as,

d1 = new Date(2014, 7)     // 08/2014   (month - 1)
d2 = new Date(2014, 1)     // 02/2014

Now check,

Date.parse(d1) > Date.parse(d2)

Date.parse() , parses a string representation of a date and returns the number of milliseconds since 1 January, 1970, 00:00:00, local time.

Answer 3

Date objects can be compared with each other. So instead of parsing them you can do it as date object itself.

function isDateGreaterThanToday(b) {
    var dS = b.split("/");
    var d1 = new Date(dS[1], (+dS[0] - 1));
    var today = new Date();
    if (d1 > today) {
        return "D is greater";
    } else {
        return "today is greater";
    }
}

console.log(isDateGreaterThanToday("08/2014"))

JSFiddle

Answer 4

You're nearly there ... Using the split method to create an array out of your date

this.isDateGreaterThanCurrent=function(b){

var a = b.split('/');

if(parseInt(a[1])>parseInt(new Date().getFullYear())) return true;
else if (parseInt(a[1]) == parseInt(new Date().getFullYear()) && parseInt(a[0])>parseInt(new Date().getMonth())+1)return true;

else return false;
};

dont forget getMonth returns values from 0 to 11, not from 1 to 12 !

Answer 5

To compare two date which are in your format, we have to parse the dates and extract the month and year and compare them

Its preffered to use some third party library

1. datejs
2. momentjs

If you want to do this manually the sample code looks like

function checkMonths(month1, month2) {
        var m1 = month1.split("/");
        var m2 = month2.split("/");
        var res = -1;

        if( parseInt(m1[1] ) > parseInt(m2[1]) ) {
            res = 1;
        } else if(parseInt(m1[1] ) == parseInt(m2[1])) {
            if(parseInt(m1[0] ) > parseInt(m2[0])) {
                res = 1;
            } else if(parseInt(m1[0] ) == parseInt(m2[0])) {
                res = 0;
            } 
        }
        return res;
}

Working demo JSFiddle demo