function openPopup(filename, popupname) {

	 var width, height;
	 var screenwidth, screenheight;
	 var agt = navigator.userAgent.toLowerCase();
	 var isNetscape = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1) && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1) && (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1));
	 var isMac = (navigator.appVersion.indexOf("Mac") != -1);
		
     var xpos, ypos;
	 //var url='main.php?<?=$MAINPARAMS;?>';


	 screenwidth = (screen.availWidth ? screen.availWidth : 800);
	 screenheight = (screen.availHeight ? screen.availHeight : 600);

	 width = 850;
	 height = 700;
	 
	 height -= 10;
	 
	 if (isMac)
	  height -= 20;
	 else
	  width -= 10;

	 xpos = (screenwidth/2)-(width/2);
	 ypos = (screenheight/2)-(height/2);



	 var winObj = window.open(filename, "", "left="+xpos+ ",top=" + ypos + ",width=" + width + ",height=" + height + ", toolbar=no, location=no, status=yes, menubar=no,scrollbars=yes, resizable=yes, copyhistory=no");

	 /*
	 if(winObj && isMac && winObj.moveTo && winObj.resizeTo) {
	  winObj.moveTo(0, 0);
	  winObj.resizeTo((width-10), height);
	 }
	 */
	 winObj.focus();
}


function interruptSurvey(){
	if(confirm("You are about to interrupt the survey. You may complete the survey later using your authentication code. Click OK to interrupt the survey now.")){
		location.href = "./inc/survey_interrupt.php";
	}
}