Need to delete all child bookmarks

You can use this code to do it:

if (this.bookmarkRoot.children!=null) {
	for (var i=0; i<this.bookmarkRoot.children.length; i++) {
		var bkm = this.bookmarkRoot.children[i];
		if (bkm.children!=null) {
			for (var j=bkm.children.length-1; j>=0; j--) {
				bkm.children[j].remove();
			}
		}
	}
}