var newDt=new Date(dt.replace("-","/"));

Date.prototype.format = function(format){
var o = {
"M+" : this.getMonth()+1, //month
"d+" : this.getDate(), //day
"h+" : this.getHours(), //hour
"m+" : this.getMinutes(), //minute
"s+" : this.getSeconds(), //second
"q+" : Math.floor((this.getMonth()+3)/3), //quarter
"S" : this.getMilliseconds() //millisecond
};
if(/(y+)/.test(format)) {
format = format.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length));
}
for(var k in o) {
if(new RegExp("("+ k +")").test(format)) {
format = format.replace(RegExp.$1, RegExp.$1.length==1 ? o[k] : ("00"+ o[k]).substr((""+ o[k]).length));
}
}
return format;
};

var fmtDt=newDt.format("yyyy-MM-dd");

var fmtDt=Convert.ToDateTime(dt).ToString("yyyy-MM-dd");