XPath to find elements that does not have an id or class

How can I get all tr elements without id attribute?

<tr id="name">...</tr>
<tr>...</tr>
<tr>...<开发者_如何学Python;/tr>

Thanks

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Pretty straightforward:

//tr[not(@id) and not(@class)]

That will give you all tr elements lacking both id and class attributes. If you want all tr elements lacking one of the two, use or instead of and:

//tr[not(@id) or not(@class)]

When attributes and elements are used in this way, if the attribute or element has a value it is treated as if it's true. If it is missing it is treated as if it's false.

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If you're looking for an element that has class a but doesn't have class b, you can do the following.

//*[contains(@class, 'a') and not(contains(@class, 'b'))]

Or if you want to be sure not to match partial.

//*[contains(concat(' ', normalize-space(@class), ' '), ' some-class ') and 
not(contains(concat(' ', normalize-space(@class), ' '), ' another-class '))]

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Can you try //tr[not(@id)]?