Using eval() to set global variables

Question

My code to set a global variable using eval is not working. It\'s as if the assignment is not called at all, but no script errors occur.

Answer 1

You could use window.eval() to run eval() from global scope. This will assign var as a variable of window, which is what a global variable is: a variable attached to window.

... But you really really shouldn't. eval() is sandboxed for a reason.

That is not unless you really know what you are doing and trust everything you are receiving through XMLHttpRequest. It is one of those chicken/egg things: if you trust the code enough to execute it, it should be programmed well enough to prefix global variables with window. to begin with; thus, you should not need to use window.eval().

Besides, unless you are just trying to avoid async headaches by using the more-manageable XMLHttpRequest (there's a first time for everything...), you really should just create a script tag, assign it's source, and append it as a child to the head or body tag. Dynamically appending script tags is even faster than using XHR, especially for big scripts.