var reg = /^([2][2][4-9]|[2][3][0-9])(\.([1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]|[1-9][0-9]|[0-9])){0,2}\.([1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]|[1-9][0-9]|[0-9])$/;试试这个
var rx = /^2[2-3][4-9](\.(\d|([1-9]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))){3}$/
var reg = /^([2][2][4-9]|[2][3][0-9])(\.([1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]|[1-9][0-9]|[0-9])){3}$/;之前的写错了,蛋疼~~
var reg=/^2[2-3][4-9](\.(\d|[1-9][0-9]|[1]\d\d|[2][0-5][0-5])){3}$/;
$patten = '/^(([1-2]|([1-2]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))\.)((d|([1-9]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))\.){2}([1-9]|([1-9]\d)|(1\d\d)|(2([0-4]\d|5[0-5])))$/';
var reg=/^2[2-3][4-9](\.(\d|[1-9][0-9]|[1]\d\d|[2][0-5][0-5])){3}$/;