function popup(URL, width, height, id) {
	    x = (640 - width)/2, y = (480 - height)/2;

    if (screen) {
        y = (screen.availHeight - height)/2;
        x = (screen.availWidth - width)/2;
    }
        var autoResizeWin=window.open(URL,id,'width='+width+',height='+height+',screenX='+x+',screenY='+y+',top='+y+',left='+x);
		if(autoResizeWin)
			return false;
		else
			return true;
	}
    
    //-----------------------------------------
    
    function callback(){

     if(document.frmcallback.fullname.value==""){
        document.frmcallback.fullname.style.background = "#FFDFDF";
        document.frmcallback.fullname.focus(); 
        return false;
    }
    if(document.frmcallback.phone.value==""){
        document.frmcallback.phone.style.background = "#FFDFDF";
        document.frmcallback.phone.focus(); 
        return false;
    }
    
        if(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(document.frmcallback.email.value)){}
    else{
	   document.frmcallback.email.style.background = "#FFDFDF";
       document.frmcallback.email.focus(); 
	   return false;
	}
     
    

}