I really do not think this is a bug.
function createHandler (num) {
return function (e) {
e = e || window.event;
alert(num);
};
}
function setup () {
document.getElementById('but').onclick = createHandler(123);
}
When you do onclick = createHandler(123); onclick gets the return value of createHandler which is a function. The alert in that function is no longer in the context of createHandler and therefore should not have access to the variable num as it no longer exists in that scope.
In order to do the same thing, I would write it as:
function handler (num, e) {
e = e || window.event;
alert(num);
}
function setup () {
// Add code to the onclick handler sending a value to the handler
// function
document.getElementById('but').onclick = "handler(123, event);";
}
Anyhow, just my two cents. I work for a company that places js probes that are placed on other companies websites that insert themselves in to various page events (while maintaining the original events), in order to do page personalization, customer reactivation, and customer tracking. I have to deal with these issues every day, even though I am really a back end code/tools guy.
By the way, I was impressed by the drawing tool.
