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Posted By

tylerhall on 11/02/06


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javascript node DOM functions utility traversal next previous


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DOM Traversal Helper Functions

 / Published in: JavaScript
 

URL: http://developer.mozilla.org/en/docs/Whitespace_in_the_DOM

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.

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  1. function is_all_ws(nod) { return !(/[^\t\n\r ]/.test(nod.data)); }
  2. function is_ignorable(nod) { return (nod.nodeType == 8) || ((nod.nodeType == 3) && is_all_ws(nod)); }
  3. function node_before(sib) {
  4.   while ((sib = sib.previousSibling)) {
  5.     if (!is_ignorable(sib)) return sib;
  6.   }
  7.   return null;
  8. }
  9. function node_after(sib) {
  10.   while ((sib = sib.nextSibling)) {
  11.     if (!is_ignorable(sib)) return sib;
  12.   }
  13.   return null;
  14. }
  15. function first_child(par) {
  16.   var res = par.firstChild;
  17.   while(res) {
  18.     if(!is_ignorable(res)) return res;
  19.     res = res.nextSibling;
  20.   }
  21.   return null;
  22. }
  23. function last_child(par) {
  24.   var res = par.lastChild;
  25.   while(res) {
  26.     if(!is_ignorable(res)) return res;
  27.     res = res.previousSibling;
  28.   }
  29.   return null;
  30. }

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