Get Day Name from Date

JavaScript

var days = ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'],
    months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];


function fromDate(date){
    var da = date.split('/');   
    return getDay(da[0], da[1], da[2]);
}

function getDay(month, day, year){
    if(!year){year = new Date().getYear();}
    else{year = year - 1900;}
    if(isNaN(month)){month = months.indexOf(month)+1;}
    return days[new Date(year, month, day).getDay()];
}

$('body').append( '1:' + getDay('2','3','2017') + '<br/>');
$('body').append( '2:' + getDay('4','2') + '<br/>');
$('body').append( '3:' + getDay(4,2) + '<br/>');
$('body').append( '4:' + getDay('April','2') + '<br/>');
$('body').append( '5:' + fromDate('4/2/2015') + '<br/>');
$('body').append( '6:' + fromDate('4/2') + '<br/>');