function validate_form ( form, def_class, err_class ) 
{
	var form_ok = true;
	for(var i = 0; i < form.elements.length; i++)
	{
		var element = form.elements[i];
        if ( (element.className == def_class) || (element.className == err_class) )
		{
      		if( (element.value.length==0) || (element.value==null) )		
      		{
      			form_ok = false;						
      			element.className = err_class ;
      		}
      		else element.className = def_class ;
      	}
	}	
	
	if ( !form_ok )		alert ( "veuillez remplir les champs manquants" );
	return ( form_ok );
}

function validate_checkbox ( form, name, def_class, err_class )
{
	var form_ok = false;
	for(var i = 0; i < form.elements.length; i++)
	{
		var element = form.elements[i];
		if ( (element.type == "checkbox") && (element.id == name) )
		{
			if ( (element.className == def_class) || (element.className == err_class) )
			{	
      			if( element.checked == true )		
      			{
      				form_ok = true;						
      			}
      			else element.className = def_class ;
      		}
		}	
	}
	if ( !form_ok )		
	{
		alert ( "veuillez choisir au moins un " + name );
		for(var i = 0; i < form.elements.length; i++)
		{
			var element = form.elements[i];
			if ( (element.type == "checkbox") && (element.id == name) )
			{
				element.className = err_class ;
			}
		}
	}

	return ( form_ok );
}