this code calls js error in IE7

var parentCell = $(this).parent(); //this - is a anchor(<a>) element in table cell (<td>) element necessary
parentCell.removeAttr('rowspan');

jquery crushing code:

// Use this for any attribute in IE6/7
// This fixes almost every IE6/7 issue
nodeHook = jQuery.valHooks.button = {
	get: function( elem, name ) {
		var ret;
		ret = elem.getAttributeNode( name );
		return ret && ( fixSpecified[ name ] ? ret.value !== "" : ret.specified ) ?
			ret.value :
			undefined;
	},
	set: function( elem, value, name ) {
		// Set the existing or create a new attribute node
		var ret = elem.getAttributeNode( name );
		if ( !ret ) {
			ret = document.createAttribute( name );
			elem.setAttributeNode( ret );
		}
		return ( ret.value = value + "" ); // !!! crashed here. ret.value = 40, value = ""
	}
};

stack trace:

removeAttr

each

jQuery.each

jQuery.removeAttr

jQuery.attr

nodeHook.set