closures - Understanding throttle in javascript the correct way -

hi i'm trying understand throttling in javascript. have code

function runonce(fn, ms) {    if(typeof(fn) !== "function")      return;    ms = ms || 5000;    var active;            return (function() {    	           	if(active) {                     console.log('no hurry please');                    } else {                active = settimeout(fn, ms);                    }            })();        };

i want test using 2 different functions callback

function x() {    console.log('timeout x'); } function y() {     console.log('timeout y'); } 

now here questions: calling runonce(x);runonce(x);runonce(x); multiple times, throttle function seems ok (only invoke function x 1 time)

1. but why "console.log('no hurry please');" never invoked?

when call runonce(x);runonce(x);runonce(y);runonce(y); function x , function y called 1 time, good.

2. but why if call runonce(x);runonce(y);runonce(x);runonce(y);, both function x , function y called 2 times?

thanks

the problem in runonce code. solved if move var active outside of function (thanks @andreas link). , repair function bit. following full code work:

var active, fnarray = [];    function runonce(fn, ms) {    if (typeof(fn) !== "function")      return;    ms = ms || 5000;    return (function() {      if (active && fnarray.indexof(fn.name) >= 0) {        console.log('no hurry please');      } else {        fnarray.push(fn.name);        active = settimeout(function() {          fnarray = fnarray.filter(function(elm) {            elm !== fn.name          });          fn();        }, ms);      }    })();  };    function x() {    document.body.innerhtml += 'timeout x </br>';  }    function y() {    document.body.innerhtml += 'timeout y </br>';  }  runonce(x);  runonce(x);  runonce(x);  runonce(y);  runonce(x);  runonce(y);