js判断选择时间不能小于当前时间的示例代码

var controldate;
function checkDate(){
controldate= document.getElementById("sendDate").value;
if(controldate==""){
alert('日期不能为空');
return false;
}else{
var day = new Date(); var Year = 0;
var Month = 0;
var Day = 0;
var CurrentDate = "";
//初始化时间
Year = day.getFullYear();
Month = day.getMonth()+1;
Day = day.getDate();

CurrentDate += Year + "-";

if (Month >= 10 )
{
CurrentDate += Month + "-";
}
else
{
CurrentDate += "0" + Month + "-";
}
if (Day >= 10 )
{
CurrentDate += Day ;
}
else
{
CurrentDate += "0" + Day ;
} //alert(CurrentDate);//当前日期

var startDate = new Date(CurrentDate.replace("-",",")).getTime() ;
var endDate = new Date(controldate.replace("-",",")).getTime() ; if( startDate > endDate )
{
alert('选择日期不能小于当前日期！');
document.getElementById("sendDate").focus();
return false;
}else{
return true;
}
}
}