我编写了一个jQuery插件,可以在桌面和移动设备上使用。我想知道是否有一种方法可以用JavaScript来检测设备是否具有触摸屏功能。我使用jquery-mobile.js来检测触摸屏事件,它适用于iOS, Android等,但我也想根据用户的设备是否有触摸屏来编写条件语句。

这可能吗?


当前回答

我喜欢这个:

function isTouchDevice(){
    return window.ontouchstart !== undefined;
}

alert(isTouchDevice());

其他回答

jQuery扩展支持对象:

jQuery.support.touch = 'ontouchend' in document;

现在你可以在任何地方检查它,像这样:

if( jQuery.support.touch )
   // do touch stuff

我使用:

if(jQuery.support.touch){
    alert('Touch enabled');
}

jQuery mobile 1.0.1

如果你测试document.documentElement中支持touchstart,这就很简单了

var x = 'touchstart'在document.documentElement; console.log (x) //如果支持返回true //否则返回false

这个问题

由于混合设备使用触摸和鼠标输入的组合,你需要能够动态地改变状态/变量,控制一段代码是否应该运行,如果用户是触摸用户或不是。

触控设备也可以在点击时触发鼠标移动。

解决方案

Assume touch is false on load. Wait until a touchstart event is fired, then set it to true. If touchstart was fired, add a mousemove handler. If the time between two mousemove events firing was less than 20ms, assume they are using a mouse as input. Remove the event as it's no longer needed and mousemove is an expensive event for mouse devices. As soon as touchstart is fired again (user went back to using touch), the variable is set back to true. And repeat the process so it's determined in a dynamic fashion. If by some miracle mousemove gets fired twice on touch absurdly quickly (in my testing it's virtually impossible to do it within 20ms), the next touchstart will set it back to true.

在Safari iOS和Chrome for Android上进行了测试。

注意:不是100%确定的指针事件为MS Surface等。

Codepen演示


const supportsTouch = 'ontouchstart' in window;
let isUsingTouch = false;

// `touchstart`, `pointerdown`
const touchHandler = () => {
  isUsingTouch = true;
  document.addEventListener('mousemove', mousemoveHandler);
};

// use a simple closure to store previous time as internal state
const mousemoveHandler = (() => {
  let time;
  
  return () => {
    const now = performance.now();

    if (now - time < 20) {
      isUsingTouch = false;
      document.removeEventListener('mousemove', mousemoveHandler);
    }

    time = now;
  }
})();

// add listeners
if (supportsTouch) {
  document.addEventListener('touchstart', touchHandler);
} else if (navigator.maxTouchPoints || navigator.msMaxTouchPoints) {
  document.addEventListener('pointerdown', touchHandler);
}

您可以使用以下代码:

function isTouchDevice() {
   var el = document.createElement('div');
   el.setAttribute('ongesturestart', 'return;'); // or try "ontouchstart"
   return typeof el.ongesturestart === "function";
}

来源:detection touch-based browsing and @mplungjan post。

上述解决方案是基于检测事件的支持,没有浏览器嗅探文章。

您可以在下面的测试页面检查结果。

请注意,上面的代码只测试浏览器是否支持触摸,而不是设备本身。所以如果你的笔记本电脑有触摸屏,你的浏览器可能不支持触摸事件。最新的Chrome浏览器支持触摸事件,但其他浏览器可能不支持。

你也可以试试:

if (document.documentElement.ontouchmove) {
  // ...
}

但它可能不适用于iPhone设备。