< div >1
$(".one div").css("background","red") // All DIV descendant elements after .one (descendents: including sons and grandsons...)
$(".one > div").css("background","red") // Child elements after .one. (Son: son and daughter....)
$(".one div").css("background","red") // Adjacent elements after .one. It is the sibling element immediately after .one. There is only one
$(".one").next().css("background","red") // This function is the same as above
$(".one ~ div").css("background" ,"red") //The sibling element after .one. Excluding the previous
$(".one").nextAll().css("background","red") //The function is the same as above
$(".one").siblings().css( "background","red") // All sibling elements of .one, whether they are behind or in front.