Introduction to the use of two common methods of function calling in js_javascript skills

A js function

function test(aa){
window.alert("你输入的是"+aa);
}

Method 1: Call

test("dddd");

Method 2: Assign function to variable

var abc=test;

abc('China');//Use variables to call functions

Note:

When we write it in this form, var abc=test("dddd"); cannot call the function through the variable abc.

This way of writing will assign the return value to abc when test has a return value. When there is no return value, the value of abc is undefined.

Specially emphasize that js naturally supports variable parameters

//编写一个函数，可以接受任意多个数，并计算他们的和
//无法重载，abc2函数名不能重复
function abc2(n1){// 可以无视参数n1
//在js中有一个arguments，可以访问所有传入的值。
//window.alert(arguments.length);
//遍历所有的参数
for(var i=0;i<arguments.length;i++){
window.alert(arguments[i]);
}
}