Case 1: Find the maximum value of any number (the use of arguments)
<script>
// 函数声明
function getMax() {
console.log(arguments);
console.log('-----');
var max = arguments[0]; //使max的值取数组第一个元素的值
for (var i = 1; i < arguments.length; i++) {
if (max < arguments[i]) {
//将max与数组中其它元素相比
max = arguments[i];
}
}
console.log(max);
}
//函数调用
getMax(9, 2, 8, 7, 22, 666, 5);
</script>
When you are not sure how many parameters are passed, you can use arguments to get them. In JavaScript, arguments are actually a built-in object of the current function. All functions have a built-in arguments object, and all the passed actual parameters are stored in the arguments object.
Case 2: Flip the array
<script>
// 函数声明
function reverse(arr) {
var newArr = [];
for (var i = arr.length - 1; i >= 0; i--) {
newArr[newArr.length] = arr[i];
}
console.log(newArr);
}
//函数调用
var arr = [9, 2, 8, 7, 22, 666, 5];
reverse(arr);
</script>
ps: array [array.length] = new data
Case 3: Bubble sort
<script>
// 函数声明
function sort(arr) {
for (var i = 1; i <= arr.length - 1; i++) {
for (var j = 0; j <= arr.length - i - 1; j++)
if (arr[j] > arr[j + 1]) {
//此时结果从小到大顺序排列，如果改为<,则结果从大到小顺序排列
var temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
console.log(arr);
}
//函数调用
var arr = [9, 2, 8, 7, 22, 666, 5];
sort(arr);
</script>
Case 4: Determine leap year
<script>
// 函数声明
function judgeYear(year) {
if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
//能被4整除且不能被100整除 或者 能被400整除
console.log('闰年');
} else {
console.log('平年');
}
}
//函数调用
judgeYear(2021);
</script>