js date comparison, time and milliseconds in js are converted to each other

Compare the size of two dates

 

var a = Date.UTC(year, month, day, hour, minute, second);
var b = Date.UTC(year, month, day, hour, minute, second);
if (a>b) {
    alert(" a>b");
} else if (a<b) {
    alert("a<b");
} else {
    alert("a=b");
}

 

Convert time to milliseconds in js

 

js convert millisecond time to datetime

 

 

var oldTime = (new Date("2012/12/25 20:11:11")).getTime(); //Get the number of milliseconds  

 

 

//Times that are not in the above format need to be converted

 

 

   //starttime ='2012-12-25 20:17:24';

    starttime = starttime.replace(new RegExp("-","gm"),"/");

    var starttimeHaoMiao = (new Date(starttime)).getTime(); //Get the number of milliseconds

 

 

[2] Convert milliseconds to time

 

 

var oldTime = (new Date("2012/12/25 20:11:11")).getTime(); //Get the number of milliseconds  

var newTime = new Date(oldTime); //get the normal time