javascript日期比较 js日期相差天数计算

var s1 = "2007-01-01";
var s2 = "2007-12-31";

s1 = s1.replace(/-/g, "/"); 
s2 = s2.replace(/-/g, "/"); 
s1 = new Date(s1);
s2 = new Date(s2);

var times= s1.getTime() - s2.getTime(); 
var days = parseInt(times/ (1000 * 60 * 60 * 24));

alert("相差天数: " + days);