JavaScript implements code access control through module mode

<script type= "Text/javascript" >//using the var keyword in anonymous functions(function(){        varPrivatefield = 42; functionInnerfunc () {notsoprivate=43; returnnotsoprivate; } alert (Privatefield); // thePrivatefield = Innerfunc ();//alert (notsoprivate);// +    })(); Alert (typeofPrivatefield);//undefinedalert (notsoprivate);//43 Variable Leaks</script>

The above uses Var to prevent variables from leaking private properties

varobj = (function (){    varPrivatefield = 42; varPublicfield = "Foobar"; functionprocessinternals () {alert (' Internal stuff: ' +Privatefield); }    functionrun () {processinternals (); Alert (' Still private stuff: ' +Privatefield); Alert (' Public stuff: ' +Publicfield); }    return{publicfield:publicfield, run:run};}) (); Obj.run (); //pop-up internal, still private, Pupublicalert (Obj.publicfield);//FoobarAlert (Obj.processinternals ());//Undefinedalert (Obj.privatefield);//undefined

JavaScript implements code access control through module mode