这个问题已经在这里有一个答案：
我一直在努力，以防止结果在p标签，并从日期从表示我提交表单后，因为后来的二次程序无法从p标签读取的数据用于第二输出后消失的输入。
请帮忙！！
function Adate(){
var edate= document.getElementById("dob").value;
var res = document.getElementById("result");
var tday = new Date();
var bdate = new Date(edate);
var agedate= tday.getFullYear() - bdate.getFullYear();
if(agedate>=0)
{
res.textContent ="You are "+agedate ;
}
else
{
res.textContent ="You are from the future!!";}
}<body>
<form onsubmit="return Adate()">
Enter your DOB:
<input type="date" id = "dob" >
<input type="submit" value ="submit">
</form>
<p id="result">
</p>
</body>只需添加return false;的功能Adate()结束，这应该做的伎俩：
function Adate(){
var edate= document.getElementById("dob").value;
var res = document.getElementById("result");
var tday = new Date();
var bdate = new Date(edate);
var agedate= tday.getFullYear() - bdate.getFullYear();
if(agedate>=0)
{
res.textContent ="You are "+agedate ;
}
else
{
res.textContent ="You are from the future!!";}
return false;
}<body>
<form onsubmit="return Adate()">
Enter your DOB:
<input type="date" id = "dob" >
<input type="submit" value ="submit">
</form>
<p id="result">
</p>
</body>在这里，return false;基本上意味着页面不会尝试提交表单一些后端，因此它不会刷新页面。
我的变种
var edate = document.getElementById("dob").value;
var res = document.getElementById("result");
var form = document.querySelector('form');
function Adate() {
var tday = new Date();
var bdate = new Date(edate);
var agedate = tday.getFullYear() - bdate.getFullYear();
if (agedate >= 0) {
res.textContent = "You are " + agedate;
} else {
res.textContent = "You are from the future!!";
}
setTimeout(function() {
form.submit();
},
4000
);
return false;
}<form onsubmit="return Adate()">
Enter your DOB:
<input type="date" id="dob">
<input type="submit" value="submit">
</form>
<p id="result">
</p>