var held =false;
var colour="";
var disk="";
var count=0;
var won=false;

function clicked(str,sender)
  {
	  if (won==false)
	    {
        if (held==false)
          {
       //check square is not empty and is top of pile - either at top of grid or square above is empty.
            if((str!="")&&(((sender=="l5")||(sender=="m5")||(sender=="r5"))||
				     (document.getElementById(sender.charAt(0)+(parseInt(sender.charAt(1))+1)).innerHTML=="")))
			        {
	              disk=str;
	              colour=document.getElementById(sender).style.backgroundColor;
                document.getElementById(sender).innerHTML="";
	              document.getElementById(sender).style.backgroundColor="";
	              held=true;
					      document.getElementById("grid").style.cursor="move";
			        }
	        }
	      else
	        {
        //check square is empty and is either at bottom of grid or on top of higher number than disk
            if ((str=="")&&
			        ((sender=="l1")||(sender=="m1")||(sender=="r1"))||
				     (document.getElementById(sender.charAt(0)+(parseInt(sender.charAt(1))-1)).innerHTML>disk))
				      {
                  		document.getElementById(sender).innerHTML=disk;
	              		document.getElementById(sender).style.backgroundColor=colour;
	              		held=false;
				  		document.getElementById("grid").style.cursor="pointer";
			      		count++;
			      		document.getElementById("moves").innerHTML=count;
			      		checkwon();
			          }
		      }
		  }
	}

 function checkwon()
  {
		if ((document.getElementById("r1").innerHTML==5)&&
		    (document.getElementById("r2").innerHTML==4)&&
				(document.getElementById("r3").innerHTML==3)&&
				(document.getElementById("r4").innerHTML==2)&&
				(document.getElementById("r5").innerHTML==1))
				  {
					  window.alert("Well done you've won in "+count+" moves");
						won=true;
					}
	}