JavaScript ?? ????
JavaScript ?? ????
JavaScript ??? ???? ?? ???? ????.
?? ??? ????(Parameters) ? ??? ????(Arguments)
?? ?????? ??? ??? ????? ?? ?????. ??...
}
??? ??? ? ??? ??? ????? ?????.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<p>設(shè)置參數(shù)的默認值。</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>If y ?? ??, y ||? y? true?? ??? y? ????, ??? ??? undefed? false?? ??? 0? ?????. ?? ?? ? ????? ?? ?? ???? ?? ???? ??? ?? ? ?? ?? ????? ???? ????. ?? ??? ???? ??? ? ????. Arguments ??JavaScript ???? ?? ?? ?? ??? ????.
argument ???? ?? ??? ???? ??? ???? ????. ? ???? ??? ????? ?? ?? ?? ? ????: ?? ??:<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<p>查找最大的數(shù)。</p>
<p id="demo"></p>
<script>
function findMax() {
var i, max = 0;
for(i = 0; i < arguments.length; i++) {
if (arguments[i] > max) {
max = arguments[i];
}
}
return max;
}
document.getElementById("demo").innerHTML = findMax(4, 5, 6);
</script>
</body>
</html> ?? ?? ?? ?? ???? ??? ????: <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<p>計算所有參數(shù)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>??? ???? ??The ???? ???? ????? ??? ??? ???????.
JavaScript ??? ????? ??? ?????. ??? ?? ?????. ??? ???? ?? ???? ?? ??? ????(?? ???? ???)? ?? ?? ???? ????. ??? ????? ?? ??? ?? ??? ???? ????. ??? ?? ???? ??JavaScript??? ??? ?? ??? ? ????.??? ?? ???? ??? ??? ???? ??? ???? ?????.
?? ?? ??? ??(?? ??) ???? ??? ? ????.
??? ?? ??? ?? ???? ? ? ????.
