Javascript set time string to date object

Question

Please see the below code;

var d = new Date();
var s = "01.00 AM";
d.setTime(s);

I know this code is wrong. Please give me the correct way to set the time. I have 12 hour time in string format in my hand.

The time will vary. Cannot know what will be the time earlier. Also it is 12 hour time. So it will be AM or PM

Answer 1

You can parse the time with a regex, and set the hours and minutes accordingly:

http://jsfiddle.net/54VkC/1/

var d = new Date(),
    s = "01.25 PM",
    parts = s.match(/(\d+)\.(\d+) (\w+)/),
    hours = /am/i.test(parts[3]) ? parseInt(parts[1], 10) : parseInt(parts[1], 10) + 12,
    minutes = parseInt(parts[2], 10);

d.setHours(hours);
d.setMinutes(minutes);

alert(d);

Edit 1: As jaisonDavis pointed out, the original code will not work for AM or PM for 12.XX, which was an oversight since I never use 12-hour format myself, thinking it started at 00.00 which was wrong.

The corrected code which handles these cases can be seen here:

http://jsfiddle.net/54VkC/93/

var test, parts, hours, minutes, date,
    d = (new Date()).getTime(),
    tests = ['01.25 PM', '11.35 PM', '12.45 PM', '01.25 AM', '11.35 AM', '12.45 AM'],
    i = tests.length,
    timeReg = /(\d+)\.(\d+) (\w+)/;

for(; i-- > 0;) {
    test = tests[i];
    
    parts = test.match(timeReg);
    
    hours = /am/i.test(parts[3]) ?
        function(am) {return am < 12 ? am : 0}(parseInt(parts[1], 10)) :
        function(pm) {return pm < 12 ? pm + 12 : 12}(parseInt(parts[1], 10));
    
    minutes = parseInt(parts[2], 10);
    
    date = new Date(d);
    
    date.setHours(hours);
    date.setMinutes(minutes);
    
    console.log(test + ' => ' + date);
}

Answer 2

I'm late to the party, but I thought I'd share a funtion that doesn't use regex:

function setDateTime(date, time) {
    var index = time.indexOf("."); // replace with ":" for differently displayed time.
    var index2 = time.indexOf(" ");

    var hours = time.substring(0, index);
    var minutes = time.substring(index + 1, index2);

    var mer = time.substring(index2 + 1, time.length);
    if (mer == "PM"){
        hours = hours + 12;
    }


    date.setHours(hours);
    date.setMinutes(minutes);
    date.setSeconds("00");

    return date;
}