我有一个带有“Date”元素的HTML表单和一个提交按钮。有2个功能。一个用于在“date”HTML元素中计算从出生日期开始的年龄。另一个功能是将年龄与允许的最小年龄进行比较。我需要帮助来完成它。在代码中的备注中查看我的问题。是的，我看过其他类似的问题。我想学习而不仅仅是复制/粘贴。如果我理解我的代码/语法有什么问题，那么我会更好地学习。提前谢谢。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
var minAge = 18;
var curDate = new Date();
var curr_year = curDate.getFullYear();
var curr_month = curDate.getMonth();
//Calculates age from given Birth Date in the form//
function _calcAge() {
var dt1 = document.getElementById('date').value;
var birth_date = new Date(dt1);
var birth_year = birth_date.getFullYear();
var birth_month = birth_date.getMonth();
var calc_year = curr_year - birth_year;
var calc_month = curr_month - birth_month;
//The following below is what I am not sure about.
//I need to combine years and months and
//convert them into a string??? Is this syntax dead wrong?
var final_result = (calc_year && "." && calc_month).toString();
// final result should be a number with a decimal point, example: 35.5
final_result = parseFloat;
return (final_result);
alert(final_result);
}
//Compares calculated age with minimum age and acts according to rules//
function _setAge() {
var age = _calcAge();
//alert("my age is " + age);
if (age < minAge) {
alert("You are not allowed into the site. The minimum age is 18!");
} else
alert("Welcome to my Site");
window.open(main.htm, _self);
}
</script>
<form>
Date Of Birth: <input type="date" name="date of birth" id="date" />
<input type="submit" name="submit" id="submit" onClick="_setAge();" />
</form>
</body>
</html>
答案 0 :(得分：3)
您可以通过基本数学函数添加或减去javascript日期。
只需为今天var Today = new Date()创建一个新日期，然后从表单中减去日期。你得到的差异在几毫秒。
现在您只需将它们除以(1000*60*60*24*365)
所以就这样做：
var difference = (curDate - birth_date)/((1000*60*60*24*365);
var differenceString = "The difference is: " + difference.toFixed(1) + " years.";
toFixed(1);以小数点后1位返回您的号码。
始终记得JavaScripts Dates Months从零开始。
你的第二个功能也应该起作用。
答案 1 :(得分：2)
这样就可以用这个
代替代码<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
var minAge = 18;
function _calcAge() {
var date = new Date(document.getElementById("date").value);
var today = new Date();
var timeDiff = Math.abs(today.getTime() - date.getTime());
var age1 = Math.ceil(timeDiff / (1000 * 3600 * 24)) / 365;
return age1;
}
//Compares calculated age with minimum age and acts according to rules//
function _setAge() {
var age = _calcAge();
//alert("my age is " + age);
if (age < minAge) {
alert("You are not allowed into the site. The minimum age is 18!");
} else
alert("Welcome to my Site");
window.open(main.htm, _self);
}
</script>
<form>
Date Of Birth:
<input type="date" name="date of birth" id="date" />
<input type="submit" name="submit" id="submit" onclick="_setAge();" />
</form>
</body>
</html>
答案 2 :(得分：0)
我设法让它发挥作用。对于我从他那里借来的部分，我还要归功于https://stackoverflow.com/users/444991/matt： https://stackoverflow.com/a/4076440/3189118
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
var minAge = 18;
var today = new Date()
//Calculates age from given Birth Date in the form//
function _calcAge(birthDate, givenDate) {
givenDate = new Date(today);
var dt1 = document.getElementById('date').value;
var birthDate = new Date(dt1);
var years = (givenDate.getFullYear() - birthDate.getFullYear());
if (givenDate.getMonth() < birthDate.getMonth() ||
givenDate.getMonth() == birthDate.getMonth() && givenDate.getDate() < birthDate.getDate()) {
years--;
}
return years;
}
//Compares calculated age with minimum age and acts according to rules//
function _setAge() {
var age = _calcAge();
if (age < minAge) {
alert("You are not allowed into the site. The minimum age is 18!");
} else
alert("Welcome to my Site");
}
</script>
<form>
Date Of Birth: <input type="date" name="date of birth" id="date" />
<input type="submit" name="submit" id="submit" onClick="_setAge();" />
</form>
答案 3 :(得分：0)
尝试一下。
<!DOCTYPE html>
<html lang="en">
<head>
<title>Person Details</title>
</head>
<body>
<form>
Birthday: <input type="date" name="bday" id="birth_date">
<br><br>
</form>
<button onclick="myFunction()">view</button><br>
<p id="age"></p>
<script>
function myFunction() {
var dobString = document.getElementById("birth_date").value;
var calculatedValue = calculate_age(dobString);
}
function calculate_age(dobString) {
var diff_ms = Date.now() - Date.parse(dobString);
var yearString = "";
var monthString = "";
var dayString = "";
var yearValue = Math.floor(diff_ms / 31536000000);
console.log("Years ", yearValue);
var monthValue = Math.floor((diff_ms % 31536000000) / 2592000000);
console.log("Months ", monthValue);
var dayValue = Math.floor(((diff_ms % 31536000000) % 2592000000) / 86400000);
console.log("Days ", dayValue);
// var calculatedValue = yearValue + " years " + monthValue + " months " + dayValue + " days"; // calculate and execute age
if (yearValue > 1) yearString = " years";
else yearString = " year";
if (monthValue > 1) monthString = " months";
else monthString = " month";
if (dayValue > 1) dayString = " days";
else dayString = " day";
if ((yearValue > 0) && (monthValue > 0) && (dayValue > 0))
var calculatedValue = yearValue + yearString + " " + monthValue + monthString + " " + dayValue + dayString + " ";
else if ((yearValue > 0) && (monthValue > 0) && (dayValue == 0))
var calculatedValue = yearValue + yearString + " " + monthValue + monthString + " ";
else if ((yearValue > 0) && (monthValue == 0) && (dayValue > 0))
var calculatedValue = yearValue + yearString + " " + dayValue + dayString + " ";
else if ((yearValue == 0) && (monthValue > 0) && (dayValue > 0))
var calculatedValue = monthValue + monthString + " " + dayValue + dayString + " ";
else if ((yearValue == 0) && (monthValue == 0) && (dayValue > 0))
var calculatedValue = dayValue + dayString + " ";
document.getElementById("age").innerHTML = "Age : " + calculatedValue;
}`
</script>`
</body>
</html>