Changing items value via onclick isn't working

Could anyone tell me why the below code isn't working?

<input type="hidd开发者_如何学Pythonen" name="way" mode="way" value="" />

<input type="button" name="finish" value="Update & Finish" onclick="document.getElementById('way').value='continue'; document.edit_list.submit();" />

I get the error:

Error: document.getElementById("way") is null

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name and id are different attributes. Your input doesn't have an id defined.

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The element with the name property of "way" also needs an id property.

<input type="hidden" name="way" mode="way" id="way" value="" />