var over = false;
function replace(id){
	if(over){
		return;
	}
	var div1= document.getElementById(id);
	var input = document.getElementById(id+"b");
	div1.innerHTML="<img src='"+input.value+"'/>";
	over=true;
}
function returng(id){
	var div1= document.getElementById(id);
	var input = document.getElementById(id+"a");
	div1.innerHTML="<img src='"+input.value+"'/>";
	over = false;
}