How to format the date in javascript?

Number.prototype.padLeft = function(base,chr){
   var  len = (String(base || 10).length - String(this).length)+1;
   return len > 0? new Array(len).join(chr || '0')+this : this;
}
    

$('#showit').click(function(){
    var d = new Date,
        dformat = [ (d.getMonth()+1).padLeft(),
                    d.getDate().padLeft(),
                    d.getFullYear()].join('-')+
                    ' ' +
                  [ d.getHours().padLeft(),
                    d.getMinutes().padLeft(),
                    d.getSeconds().padLeft()].join(':');
     $('#result').html(dformat);
});