functions as params

[trinistorm]

I started back playing with JavaScript. I wanted to create an Ajax messaging library. The code below requests 3 parameters, the one called 'callback' expects a function.

function runAjax(param, callback, formmode){	//param[0]=>uri param[1]=> Data, callback=>built in callback function, formode=>"GET","POST" switch	console.log("Ajaxbot is in "+ajaxbot.readyState+" with http "+ajaxbot.status);	if(ajaxbot != false){		if(ajaxbot.readyState != 0){			console.log("Still in state:"+ ajaxbot.readyState+".");		}else{			try{				if(formmode != true ){					ajaxbot.onreadystatechange = function(){						if(ajaxbot.readyState == 4 && ajaxbot.status ==200){						   callback;						}					};					ajaxbot.open("GET", param[0]+param[1], true );					ajaxbot.send();				}else{					ajaxbot.onreadystatechange = function(){						if(ajaxbot.readyState == 4 && ajaxbot.status ==200){						   callback;						}					};					ajaxbot.open("POST", param[0], true );					ajaxbot.setRequestHeader("Content-type","application/x-www-form-urlencoded");					ajaxbot.send(param[1]);				}			}catch(Ex){				console.log("Unable to access requested resource: "+param[0]," "+param[1]+"!");				console.log(Ex.toString());			}		}	}else{		console.log("Failed to get Ajax Object!");	}}

After some time I realized that by passing runAjax() a callback function causes the callback to be executed as soon as runAjax() is called.So I'm thinking this is an improper use as of functions as parameters, how can I correct this so that my callback is only called during my selection statements.

[trinistorm]

Ok scratch, that I found a work around by creating an object and I just call the methods I need. However java script is strange as an OOP language, is there a way to make functions private?

function AjaxObj(){	//Properties	this.plaintext = null;	this.xml = null;	this.destid = null;	//Methods	this.dump   = dump;	this.parse  = parseResponse;	this.create = getAjaxbot;}function getAjaxbot(){	//Returns false if Ajax is not possible	var ajaxbot = false;	try{		ajaxbot = new XMLHttpRequest();	}catch(Ex){		try{			ajaxbot = new ActiveXObject("Msxml2.XMLHTTP");		}catch(Ex){			try{				ajaxbot = new ActiveXObject("Microsoft.XMLHTTP");			}catch(Ex){			}			ajaxbot = false;		}	}	return ajaxbot;}function parseResponse(callback){	//This is a method of AjaxObj	console.log("Retriving Message..\n In state "+ajaxbot.readyState+" with http code "+ajaxbot.status);		switch(callback){		case 0: //Do nothing			break;			case 1: //Dump the result to a div.				AjaxObj.prototype.plaintext = ajaxbot.responseText;								dump(AjaxObj.prototype.plaintext);				break;	}}function dump(Data){	//Dumps the server response to console and the {destid}.	document.getElementById(AjaxObj.prototype.destid).innerHTML = Data;	console.log("The Server said:\n");	console.log(AjaxObj.prototype.plaintext);}

[ShadowMage]

...is there a way to make functions private?

Just declare it inside the scope of your object:

function myObject() {   var privateVar = 'private';      function privateFunc() {	  //Do some stuff   }}

[justsomeguy]

In your original code, you're not executing the callback correctly. Instead of just this:

callback;

you need this:

callback();

You can also send that function parameters if you want, like the response object. To pass the function you just send the function name:

function run(func){  func();}function test(){  alert('test');}run(test); // pass test function to run function

You can also pass an anonymous function:

run(function() { alert('test'); });

[trinistorm]

callback();

Thanks, I didn't realize I was doing that.

function myObject() { var privateVar = 'private'; function privateFunc() { //Do some stuff }}

Thanks, what I was looking for wasn't "private access" it would have been closer to "protected access". I got the functionality by using the "this" keyword in front of each declaration.