How to Select an Arbitrary Child Element Without Knowing its Parent?

Selecting an Arbitrary Child Element Without Knowing the Parent

When dealing with dynamic code, it's common to encounter scenarios where the parent element of a target child is unknown. This poses a challenge when attempting to select specific elements using child selectors.

Nth-Child Selectors to the Rescue

Fortunately, the nth-child selector provides a solution to this problem. Unlike first-child and last-child, nth-child() can be used without specifying the parent element. It simply selects the n-th child within the current context, regardless of the parent's identity.

Example:

Consider the following HTML structure:

<youdontknowwhat>
   <p class="select-me">One</p>
   <p class="select-me">Two</p>
</youdontknowwhat>!>

To select the second paragraph, you can use the following selector:

.select-me:nth-child(2)

Why No :first, :last, or :nth Selectors?

As mentioned by BoltClock, every HTML element except the root () is a child of another element. Using selectors like :first would be ambiguous because it could refer to either the first child of the current element or the first child of the current element's parent. This ambiguity is avoided by using :first-child, :last-child, and :nth-child(), which clearly specify the scope of the selection.

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