代码：
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> </head> <body> <input type="date" id="d" value="2018-10-01"> <button onclick="getDate()">点我</button> <p id="demo"></p> <script> function getDate() { var s1 = document.getElementById("d").value; s1 = new Date(s1.replace(/-/g, "/")); s2 = new Date(); var days = s2.getTime() - s1.getTime(); var time = parseInt(days / (1000 * 60 * 60 * 24)); document.getElementById("demo").innerHTML = ‘天数：‘+time; } </script> </body> </html>
原文：https://www.cnblogs.com/raitorei/p/10636502.html