使用onclick时，coffeescript中的变量值不变

Question

I have the following Coffeescript code:

for name, data of statistics
    row = document.createElement 'tr'
    row.onclick = ->
        alert name

However, when I compile and run it (in the context of a large webpage), it alerts the same name, no matter what row I click on. It seems to be remembering the variable, as if it's constant.

What am I doing wrong?

EDIT:

I've discovered the issue, but I'm not sure how to go about fixing it: Javascript/Coffeescript does not evaluate the 'name' variable until the end of the loop is reached.

Answer 1

The functions that you are defining (and assigning to the row's onclick attribute) all have access to the same variable outside that function (name). At the end of the loop, name has one value (the last item in the loop, as you mention), so each of the onclick functions alerts that value.

You can fix this by binding 'name' to a value that doesn't change. This question presents one solution. This question has some useful background that's worth reading.