pop up window is not being displayed

[malcom p]

My pop up window is not appearing. It is suppose to appear after my validation but even though the validation is working, the pop up window is not appearing. Does anyone have any ideas:

 

    function validation() {
    	var isDataValid = true;
    	var textO = document.getElementsByName("textBox1");               
        var errMsgO = document.getElementById("txtBox1Alert");

        if (textO.value == '') {
    	   errMsgO.innerHTML = "Text Box is empty";
    	   isDataValid = false;
        } else {
    	   errMsgO.innerHTML = ""; 
        }
        if(isDataValid) {
    	   function openSessionPopup (txt) {
     		 window.open(txt, 'window', 'width=500,height=500,scrollbars=yes,status=no');
           }  
    	}  
    }
    		
    function myClickHandler(){
        if(validation()){
           showSessionPopup();
        }
    }

In Html Form:

<!-- language: lang-html -->

     <p><input class="questionBtn" type="button" value="Prepare Questions" name="prequestion" onClick="myClickHandler()"/></p> 

[nogray]

Change the following

function openSessionPopup (txt) {
    window.open(txt, 'window', 'width=500,height=500,scrollbars=yes,status=no');
} 

to

window.open('MY_URL', 'window', 'width=500,height=500,scrollbars=yes,status=no');