example1
div1
div2
span1
span2
a1
a2
*:first-child
*:nth-child(
)
*:last-child
.item:nth-child(
)
example2
div1
div2
span1
span2
a1
a2
*:first-of-type
*:nth-of-type(
)
*:last-of-type
.item:nth-of-type(
)