How do i bind multiple events to several elements using the for loop in JS?

hai. I have been learning jS lately. How do i bind multiple events to several elements using a loop? Here is an example of what i am trying 开发者_开发问答to do. Lets say i have several divs with the ids $box1, #box2, #box3 ... #box9 etc. why doesnt this work? ( im using jquery ).

for (var i; i<8; i++){
    $('#box' + i).click(function(){alert('hai')});
}

I know that i can do the same thing instead like this:

$('div').each(function(){
    $(this).click(function(){alert('hai')});
});

However i d like to know why the first code snippet wouldnt work as i intended it to.

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In javascript, simply defining a variable using var i; doesn’t make it zero and "loopable".

So you simply need to assign a number to the i variable.

for (var i = 0;

Also note that you can’t know what i is inside the callback due to JavaScript closure.