JS judging horizontal and vertical screens and prohibiting browser sliding bars

var $horizontal = $('.horizontal_screen'); //Customize the horizontal screen mode prompt style
var $document = $(document) ;
var preventDefault = function(e) {
();
};
var touchstart = function(e) {
$('touchstart touchmove', preventDefault);
};
var touchend = function(e) {
$('touchstart touchmove', preventDefault);
};

function listener(type){
if('add' == type){
//Performance mode
$('hide');
$('touchstart', touchstart);
$('touchend', touchend);
}else{
//Handwidth Mode
$('hide');
$('touchstart', touchstart);
$('touchend', touchend);
}
}
function orientationChange(){
switch() {
//Performance mode
case 0:
case 180:
listener('add');
break;
//Handwidth Mode
case -90:
case 90:
listener('remove');
break;
}
}

$(window).on("onorientationchange" in window ? "orientationchange" : "resize", orientationChange);

$(function(){
//Enter the interface in horizontal screen mode, prompting that only vertical screens are supported
if( == 90 || == -90){
listener('remove');
}
});