<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
<p>设置参数的默认值。</p>
<p id="demo"></p>
<script>
function myFunction(x, y) {
if (y === undefined) {
y = 0;
}
return x * y;
}
document.getElementById("demo").innerHTML = myFunction(4);
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
<p>设置函数参数默认值。</p>
<p id="demo"></p>
<script>
function myFunction(x, y) {
y = y || 0;
return x * y;
}
document.getElementById("demo").innerHTML = myFunction(4);
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
<p>设置参数的默认值。</p>
<p id="demo1"></p>
<p id="demo2"></p>
<script>
function myFunction(x, y = 10) {
// 如果不传入参数 y ，则其默认值为 10
return x + y;
}
// 输出 2
document.getElementById("demo1").innerHTML = myFunction(0, 2) ;
// 输出 15, y 参数的默认值
document.getElementById("demo2").innerHTML = myFunction(5);
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
<p>查找最大的数。</p>
<p id="demo"></p>
<script>
x = findMax(1, 123, 500, 115, 44, 88);
function findMax() {
var i, max = arguments[0];
if(arguments.length < 2) return max;
for (i = 0; i < arguments.length; i++) {
if (arguments[i] > max) {
max = arguments[i];
}
}
return max;
}
document.getElementById("demo").innerHTML = x;
</script>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
<p>计算所有参数之和：</p>
<p id="demo"></p>
<script>
function sumAll() {
var i, sum = 0;
for(i = 0; i < arguments.length; i++) {
sum += arguments[i];
}
return sum;
}
document.getElementById("demo").innerHTML =
sumAll(1, 123, 500, 115, 44, 88);
</script>
</body>
</html>
原文地址：https://www.cnblogs.com/tszr/p/10943556.html
时间： 2024-07-29 18:50:40