javascript node traversal function_javascript skills

A set of functions found on the Firefox official website, equivalent to treeWalker, with which you can easily implement all the functions of Traversal API 2 in IE (nextElementSibling, previousElementSibling, firstElementChild, lastElementChild, children). These functions let you find the next sibling, previous sibling , first child, and last child of a given node (element). What makes them unique is that they safely ignore whitespace nodes so you get the real node you're looking for each time.

Copy code The code is as follows:

function is_all_ws(nod) { return !(/[^tnr ]/.test(nod.data) ); }
function is_ignorable(nod) { return (nod.nodeType == 8) || ((nod.nodeType == 3) && is_all_ws(nod)); }
function node_before(sib) {
while ((sib = sib.previousSibling)) {
if (!is_ignorable(sib)) return sib;
}
return null;
}
function node_after(sib) {
while ((sib = sib.nextSibling)) {
if (!is_ignorable(sib)) return sib;
}
return null;
}
function first_child(par) {
var res = par.firstChild;
while(res) {
if(!is_ignorable(res)) return res;
res = res.nextSibling;
}
return null;
}
function last_child(par) {
var res = par.lastChild;
while(res) {
if(!is_ignorable(res)) return res;
res = res.previousSibling;
}
return null;
}