Strange things in JavaScript “for”

Question

I\'m using jQuery and I have a strange thing that I don\'t understand. I have some code:

for (i = 1; i <= some_number; i++) {
    $(\"#some_button\" + i).         


        

Answer 1

This is because of how closures work in JavaScript. Each of the 5 functions you are creating is basically sharing the same i variable. The value of i inside your function is not being evaluated when you are creating the function, but when the click event occurs, by which time the value of i is 5.

There are various techniques for getting around this (when this behavior isn't what you want). One (if you have a simple function, like you do here) is to use the Function constructor instead of a function literal:

$("#some_button" + i).click(new Function("alert("+i+")");