/**
 * This type-detection plug-in will look at an HTML string from a data cell,
 * strip the HTML tags and then check to see if the remaining data is numeric.
 * If it is, then the data can be sorted numerically with the Numbers with HTML
 * sorting plug-in.
 *  @name Numbers with HTML
 *  @anchor numbers_html
 *  @author <a href="http://sprymedia.co.uk">Allan Jardine</a>
 */

jQuery.fn.dataTableExt.aTypes.unshift( function ( sData )
{
	sData = typeof sData.replace == 'function' ?
		sData.replace( /<.*?>/g, "" ) : sData;
	sData = $.trim(sData);
	 
	var sValidFirstChars = "0123456789-";
	var sValidChars = "0123456789.";
	var Char;
	var bDecimal = false;
	 
	/* Check for a valid first char (no period and allow negatives) */
	Char = sData.charAt(0); 
	if (sValidFirstChars.indexOf(Char) == -1) 
	{
		return null;
	}
	 
	/* Check all the other characters are valid */
	for ( var i=1 ; i<sData.length ; i++ ) 
	{
		Char = sData.charAt(i); 
		if (sValidChars.indexOf(Char) == -1) 
		{
			return null;
		}
		 
		/* Only allowed one decimal place... */
		if ( Char == "." )
		{
			if ( bDecimal )
			{
				return null;
			}
			bDecimal = true;
		}
	}
	 
	return 'num-html';
} );