javascript - For loop on an object is getting out of control -

i'm working project has crazy loop expand nodes in d3.js canvas interactive. essentially, want expand children. if object has child, want expand them.

i cut out chunk of code this. there's many loops it's ridiculous. how can reduce simple "find children, preform toggle(); , update();"?

$('.expandall').click(function(e) {     e.preventdefault();     length = root.children.length;      (var = 0; < length; i++) {         toggle(root.children[i]);         update(root);          if (root.children[i]['children']) {             childlength = root.children[i]['children'].length;              (var j = 0; j < childlength; j++) {                 toggle(root.children[i]['children'][j]);                 update(root);                  if (root.children[i]['children'][j]['children']) {                     childlength2 = root.children[i]['children'][j]['children'].length;                      (var k = 0; k < childlength2; k++) {                         toggle(root.children[i]['children'][j]['children'][k]);                         update(root);                     }                 }             }         }     } }); 

sounds case recursion:

$('.expandall').click(function(e) {     e.preventdefault();      expandall(root); });  var expandall = function (node) {     toggle(node);     update(node);      // edit: if nodes no children lacking children property     if (!node.children) {         return;     }      (var = 0, length = node.children.length; < length; i++) {         expandall(node.children[i]);     } }; 

i'm not sure toggle , update means, may able perform single top-level update call after calling expandall(root);.