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/**
 * Whitespace in the DOM
 *
 * Funcoes para trabalhar com DOM no Mozilla sem considerar whitespaces
 *
 * @author L. David Baron [http://dbaron.org/]
 * @license http://creativecommons.org/licenses/by-sa/2.0/
 */

/**
 * Throughout, whitespace is defined as one of the characters
 *  "\t" TAB \u0009
 *  "\n" LF  \u000A
 *  "\r" CR  \u000D
 *  " "  SPC \u0020
 *
 * This does not use Javascript's "\s" because that includes non-breaking
 * spaces (and also some other characters).
 */

/**
 * Determine whether a node's text content is entirely whitespace.
 *
 * @param nod  A node implementing the |CharacterData| interface (i.e.,
 *             a |Text|, |Comment|, or |CDATASection| node
 * @return     True if all of the text content of |nod| is whitespace,
 *             otherwise false.
 */
function is_all_ws(nod)
{
	// Use ECMA-262 Edition 3 String and RegExp features
	return !(/[^\t\n\r ]/.test(nod.data));
}

/**
 * Determine if a node should be ignored by the iterator functions.
 *
 * @param nod  An object implementing the DOM1 |Node| interface.
 * @return     true if the node is:
 *                1) A |Text| node that is all whitespace
 *                2) A |Comment| node
 *             and otherwise false.
 */

function is_ignorable(nod)
{
	return ( nod.nodeType == 8) || // A comment node
	( (nod.nodeType == 3) && is_all_ws(nod) ); // a text node, all ws
}

/**
 * Version of |previousSibling| that skips nodes that are entirely
 * whitespace or comments.  (Normally |previousSibling| is a property
 * of all DOM nodes that gives the sibling node, the node that is
 * a child of the same parent, that occurs immediately before the
 * reference node.)
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The closest previous sibling to |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
function node_before(sib)
{
	while ((sib = sib.previousSibling))
	{
		if (!is_ignorable(sib))
			return sib;
	}
	return null;
}

/**
 * Version of |nextSibling| that skips nodes that are entirely
 * whitespace or comments.
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The closest next sibling to |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
function node_after(sib)
{
	while ((sib = sib.nextSibling))
	{
		if (!is_ignorable(sib))
			return sib;
	}
	return null;
}

/**
 * Version of |lastChild| that skips nodes that are entirely
 * whitespace or comments.  (Normally |lastChild| is a property
 * of all DOM nodes that gives the last of the nodes contained
 * directly in the reference node.)
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The last child of |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
function last_child(par)
{
	var res = par.lastChild;
	while (res)
	{
		if (!is_ignorable(res))
			return res;
		res = res.previousSibling;
	}
	return null;
}

/**
 * Version of |firstChild| that skips nodes that are entirely
 * whitespace and comments.
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The first child of |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
function first_child(par)
{
	var res = par.firstChild;
	while (res)
	{
		if (!is_ignorable(res))
			return res;
		res = res.nextSibling;
	}
	return null;
}

/**
 * Version of |data| that doesn't include whitespace at the beginning
 * and end and normalizes all whitespace to a single space. (Normally
 * |data| is a property of text nodes that gives the text of the node.)
 *
 * @param txt  The text node whose data should be returned
 * @return     A string giving the contents of the text node with
 *             whitespace collapsed.
 */
function data_of(txt)
{
	var data = txt.data;
	// Use ECMA-262 Edition 3 String and RegExp features
	data = data.replace(/[\t\n\r ]+/g, " ");
	if (data.charAt(0) == " ")
		data = data.substring(1, data.length);
	if (data.charAt(data.length - 1) == " ")
		data = data.substring(0, data.length - 1);
	return data;
}

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