javascript object prototype call

b2 and b3 are not triggering the prototype functions and no errors are generated? How does one accomplish calling prototype functions in the fashion?

<html>
<head>

<script type="text/javascript">
	function newObj(){
		this.obj_val= 7;
	}
	var trigger_f0 = function(){
		alert("here 0");										// trigger FINE! (ok)
	}
	newObj.prototype.trigger_f2 = function (){ // no triggering off click event
		alert("here 2");
	}
	newObj.prototype.trigger_f3 = function (){  // not triggering off click event
		alert("obj value:" + newObj.obj_val);
	}

	var init = function(){
		b3.addEventListener('click', newObj.trigger_f3, false);
		b2.addEventListener('click', newObj.trigger_f2, false);
		b1.addEventListener('click', trigger_f0, false);
	}

	window.addEventListener('DOMContentLoaded', init, false);
	</script>
	
	</head>
<body>
<button id="b1">B1</button>
<button id="b2">B2</button>
<button id="b3">B3</button>

</body>

</html>

Solution

You need to create an instance like to get an object out of the constructor function

var a=new newObj()

and then access the properties. and change newObj.obj_val to

new newObj().obj_val

function newObj() {
  this.obj_val = 7;
}
var trigger_f0 = function() {
  alert("here 0"); // trigger FINE! (ok)
}
newObj.prototype.trigger_f2 = function() { // no triggering off click event
  alert("here 2");
}
newObj.prototype.trigger_f3 = function() { // not triggering off click event
  alert("obj value:" + new newObj().obj_val);
}
var a = new newObj();

b3.addEventListener('click', a.trigger_f3, false);
b2.addEventListener('click', a.trigger_f2, false);
b1.addEventListener('click', trigger_f0, false);

<body>
  <button id="b1">B1</button>
  <button id="b2">B2</button>
  <button id="b3">B3</button>

</body>