如何将侦听器附加到克隆元素？

Question

I'm currently learning about DOMs and have this problem I'm struggling with when two or more cloned elements get the same event listener.

        case 116:
            var myList = document.querySelectorAll(".selected");
            for(var i=0; i<myList.length;i++)
            {
                var node=myList[i].cloneNode(true);
                node.style.top=Math.random()*window.innerHeight-(node.style.height/2)+"px";
                node.style.left=Math.random()*window.innerWidth-(node.style.width/2)+"px";
                node.addEventListener("click",function(e){
                    node.classList.toggle("selected");
                    console.log(e);
                });
                myList[i].parentNode.appendChild(node);
            }
            break;

box 1 is the original box and it has its own EventListener.

box 2 is the clone of the original and selects and deselects as it should.

box 3-4 are clones of 1-2 but it seems that box 3 and 4 get the same listener because when I click on box 4 it toggles selected on box 3 and nothing happens with box 4.

How do I solve this?

Any help will be most welcome.

Answer 1

I think this is a scoping issue. Your event handler is making reference to node , but at the end of the loop, node will point to the last square created. You can store the value of node for each event handler using a closure:

(function(node) {

    // 'node' defined here is in it's own scope, so won't be affected by the changes
    // made to the 'node' variable defined in the outer scope of the loop.
    node.addEventListener("click",function(e){
        node.classList.toggle("selected");
        console.log(e);
    });

})(node);

but probably the better solution is to use this within your event handler:

node.addEventListener("click",function(e){

    // within an event handler, 'this' references the event's target element
    this.classList.toggle("selected");
    console.log(e);
});