Self-calling function in JS (one-time function)

1. Self-invocation of function---self-calling function

function's self-invocation//one-time functions (function () {Console.log ("one-time");}) ();(function (Win) {var num=20;win.num=num;}) (window);//The local variable to the parent class can be console.log (num);

2. Generate a random number object from the self-calling function, and call the random Number object method to generate a random number outside the self-calling function

Generates a Random object (function (window) {//generates a random function () {random.prototype.getrandom=function (Min,max) { Return Math.floor (Math.random () * (max-min) +min);};/ /expose the Random object to the top-level object Window}window. Random=random;}) (window); var rm=new Random (); Console.log (Rm.getrandom (0,5));  

3. Case a random small square

<script>//Generate random Number object (function (window) {function Random () {} random.prototype.getrandom=function (min,m    AX) {return Math.floor (Math.random () * (max-min) +min);    }; Exposing a local object to a window's top-level object becomes the Global object window.  Random=new Random ();    }) (window);//The semicolon must add//produce a small square object (function (window) {//console.log (Random.getrandom (0,5)), from the way the constructor is called.    Selector for the way to get the element object var map=document.queryselector (". Map"); Food's constructor function foods (width,height,color) {this.width=width| | 20;//The default small square width this.height=height| | 20;//default Small square height//horizontal axis, ordinate this.x=0;//horizontal axis randomly generated this.y=0;//ordinate randomly generated this.color=color;//small square background color this.      Element=document.createelement ("div");//small square element}//Initialize the display effect and position of the small square---display map food.prototype.init=function (map) {      Set the style of the small square var div=this.element;      div.style.position= "Absolute";//out-of-document flow div.style.width=this.width+ "px";      div.style.height=this.height+ "px";      Div.style.backgroundcolor=this.color; Add small squares to mapMap in Map.appendchild (DIV);    This.render (map);    }; Generate random position food.prototype.render=function (map) {//randomly generate horizontal ordinate var x=random.getrandom (0,map.offsetwidth/this.widt      h) *this.width;      var y=random.getrandom (0,map.offsetheight/this.height) *this.height;      This.x=x;      This.y=y;      var div=this.element;      div.style.left=this.x+ "px";    div.style.top=this.y+ "px";    };    Instanced object var fd=new food (20,20, "green");    Fd.init (map);      Console.log (fd.x+ "= = =" +fd.y); }) (window);</script>

　　

Self-calling function in JS (one-time function)