php|architect's Guide to Web Scraping with PHP - Wind Business ...

136 ” CSS Selector Libraries
Child F i l t e r s
Child filters are fairly similar to the basic filters reviewed earlier, except applied to
child nodes.
• ul:nth-child(2) selects the second child element within each ul node. The
parameter passed to the filter can also be even or odd (which are figured relative
to child position within the parent element) or can use expressions involving
a variable n (such as 3n for every third child).
• li:first-child selects all li nodes that are the first child of their parent node.
• li:last-child likewise selects all li nodes that are the last child of their parent
node.
• li:only-child selects all li nodes that are the only child of their parent node.
Selector CSS XPath
nth child nodes ul:nth-child(2) //ul/*[position() = 2]
first child nodes li:first-child //*/*[name() = “li” and
position() = 1]
last child nodes li:last-child //*/*[name() = “li” and
position() = last()]
only child nodes li:only-child //*/*[name() = “li” and count()
= 1]
F o r m F i l t e r s
F o r m filters are just a more convenient shorthand for other expressions.
• :input matches all input, textarea, select, and button elements.
• :text, :hidden, :password, :radio, :checkbox, :submit, :image, :reset, and :file
all matches input elements with their respective types.
• :button matches all button elements and input elements of type button.