// Gets a element by its Id. Used for shorter coding.
function GetE( elementId )
{
	return document.getElementById( elementId )  ;
}

function ShowE( element, isVisible )
{
	if ( typeof( element ) == 'string' )
		element = GetE( element ) ;
	element.style.display = isVisible ? '' : 'none' ;
}

function SetAttribute( element, attName, attValue )
{
	if ( attValue == null || attValue.length == 0 )
		element.removeAttribute( attName, 0 ) ;			// 0 : Case Insensitive
	else
		element.setAttribute( attName, attValue, 0 ) ;	// 0 : Case Insensitive
}

function GetAttribute( element, attName, valueIfNull )
{
	var oAtt = element.attributes[attName] ;

	if ( oAtt == null || !oAtt.specified )
		return valueIfNull ? valueIfNull : '' ;

	var oValue ;
	
	if ( !( oValue = element.getAttribute( attName, 2 ) ) )
		oValue = oAtt.nodeValue ;

	return ( oValue == null ? valueIfNull : oValue ) ;
}

// Functions used by text fiels to accept numbers only.
function IsDigit( e )
{
	e = e || event ;
	var iCode = ( e.keyCode || e.charCode ) ;

	event.returnValue =
		(
			( iCode >= 48 && iCode <= 57 )		// Numbers
			|| (iCode >= 37 && iCode <= 40)		// Arrows
			|| iCode == 8						// Backspace
			|| iCode == 46						// Delete
		) ;

	return event.returnValue ;
}

String.prototype.trim = function()
{
	return this.replace( /(^\s*)|(\s*$)/g, '' ) ;
}

String.prototype.startsWith = function( value )
{
	return ( this.substr( 0, value.length ) == value ) ;
}

String.prototype.remove = function( start, length )
{
	var s = '' ;

	if ( start > 0 )
		s = this.substring( 0, start ) ;

	if ( start + length < this.length )
		s += this.substring( start + length , this.length ) ;

	return s ;
}