Acess Dynamically Created Elements

Hello,
I have a textbox with an empty span element (place holder) next to it.
When the user adds some text to the text box, I create a checkbox in
the empty span element. When I create the checkbox I create a unique
ID for the checkbox and associate an OnClick event with it. When I
proceede to check that checkbox, I get a javascript error stating that
the id is not defined. This is a dynamically created element, but
shouldn't the ID of that element still be added to the DOM tree for
acess via getElementByID() ?

Any ideas/solutions? More information needed?
Thanks
-Brad

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