function model_count() {
	var compare_models = Get_Cookie( 'Compare_Model' );
	if ( compare_models ){
		return compare_models.split( ',' ).length;
	}else{
		return 0;
	}
}

// add this model to comparison list
function add_model( modelid ) {
	remove_model( modelid );
	var compare_models = Get_Cookie( 'Compare_Model' );
	if ( compare_models ){
		Set_Cookie( 'Compare_Model', compare_models+','+modelid, '', '/', '', '' );
	}else{
		Set_Cookie( 'Compare_Model', modelid, '', '/', '', '' );
	}
}

// remove this model from comparison list
function remove_model( modelid ) {
	var compare_models = Get_Cookie( 'Compare_Model' );
	if ( compare_models ){
		var model_array = compare_models.split( ',' );
		if(model_array.length>0){
			var tmp = '';
			for ( i = 0; i < model_array.length; i++ ){
				if(modelid != model_array[i]){
					if(tmp == '')
						tmp = model_array[i];
					else
						tmp = tmp + ',' + model_array[i];
				}
			}
			Set_Cookie( 'Compare_Model', tmp, '', '/', '', '' );
		}else{
			Delete_Cookie('Compare_Model', '/', '');
		}
	}
}

// initial form
function init_checked_models() {
	var radio_button = document.forms["compareForm"].elements["modelID"];
	var compare_models = Get_Cookie( 'Compare_Model' );
	if ( compare_models ){
		var model_array = compare_models.split( ',' );
		for ( i = 0; i < model_array.length; i++ ){
		  	for (counter = 0; counter < radio_button.length; counter++){
				if (radio_button[counter].value == model_array[i])
					radio_button[counter].checked = true;
			}

		}
	}
}