I am wondering why the statement "let im = _imgs[i];" is indispensable in this situation. Essentially, the _imgs are an array of image elements. But if I add the eventhandlers by _imgs[i].addEventListener("click", function(){clickImage(_imgs[i]);}, false);, it won't work.

Can anyone explain why? Thanks a lot!

function init()
{
    _imgs = document.querySelectorAll("#block2 img");
    console.log(_imgs.length);
    _clicked = new Object();
    for(var i = 0; i < _imgs.length; i++)    
    {      
        let im = _imgs[i];
        _imgs[i].addEventListener("click", function(){clickImage(im);}, false);
        _clicked[_imgs[i].id] = 0;
    }
    console.log("hi");
}