js判断输入日期是否在当前日期之前

function checkTime()
{
var check = 0;
var nowDate = new Date();
var date = nowDate.getFullYear()+"年"+(nowDate.getMonth()+1)+"月"+nowDate.getDate()+"日";
var input_time = $('#time').val();
var time_split = new Array();
time_split = input_time.split("-");
if(nowDate.getFullYear() < time_split[0])
{
check = 0;
alert('当前仅能录入'+date+'之前的数据');
document.getElementById("time").select();
}
else if(nowDate.getFullYear()==time_split[0] )
{
if(nowDate.getMonth()+1 < time_split[1])
{
check = 0;
alert('当前仅能录入'+date+'之前的数据');
document.getElementById("time").select();
}
else if(nowDate.getMonth()+1 == time_split[1])
{
if(nowDate.getDate() <= time_split[2])
{
check = 0;
alert('当前仅能录入'+date+'之前的数据');
document.getElementById("time").select();
}
else
{
check = 1;
}
}
else
{
check = 1;
}
}
else
{
check = 1;
}
return check;
}