浏览器判断放大

April 19, 2024

获取当前页面浏览器的缩放大小 #

// 判断pc浏览器是否缩放，若返回100则为默认无缩放，如果大于100则是放大，否则缩小
function detectZoom (){
  var ratio = 0,
    screen = window.screen,
    ua = navigator.userAgent.toLowerCase();
   
   if (window.devicePixelRatio !== undefined) {
      ratio = window.devicePixelRatio;
  }
  else if (~ua.indexOf('msie')) {
    if (screen.deviceXDPI && screen.logicalXDPI) {
      ratio = screen.deviceXDPI / screen.logicalXDPI;
    }
  }
  else if (window.outerWidth !== undefined && window.innerWidth !== undefined) {
    ratio = window.outerWidth / window.innerWidth;
  }
     
   if (ratio){
    ratio = Math.round(ratio * 100);
  }
     
   return ratio;
};

具体实现demo #

 <!DOCTYPE html>
  <html>
  <head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>浏览器网页内容的百分比缩放（按Ctrl和+号键或者-号键的缩放）</title>
  <style type="text/css">
  </style>
  </head>
  <body>
    <a href="javascript:;" id="openApp">知乎客户端</a>
    <input type="text" name="ee" autocomplete="on">
  </body>
 </html>
<script type="text/javascript" src="js/jquery-1.11.3.min.js"></script>
<script type="text/javascript">
// 判断pc浏览器是否缩放，若返回100则为默认无缩放，如果大于100则是放大，否则缩小
function detectZoom (){
  var ratio = 0,
    screen = window.screen,
    ua = navigator.userAgent.toLowerCase();
   
   if (window.devicePixelRatio !== undefined) {
      ratio = window.devicePixelRatio;
  }
  else if (~ua.indexOf('msie')) {
    if (screen.deviceXDPI && screen.logicalXDPI) {
      ratio = screen.deviceXDPI / screen.logicalXDPI;
    }
  }
  else if (window.outerWidth !== undefined && window.innerWidth !== undefined) {
    ratio = window.outerWidth / window.innerWidth;
  }
     
   if (ratio){
    ratio = Math.round(ratio * 100);
  }
     
   return ratio;
};
//window.onresize 事件可用于检测页面是否触发了放大或缩小。
$(function(){
  //alert(detectZoom())
})
$(window).on('resize',function(){
      isScale();
});
//判断PC端浏览器缩放比例不是100%时的情况
function isScale(){
  var rate = detectZoom();
  if(rate != 100){
    //如何让页面的缩放比例自动为100,'transform':'scale(1,1)'没有用，又无法自动条用键盘事件，目前只能提示让用户如果想使用100%的比例手动去触发按ctrl+0
    console.log(1)
    alert('当前页面不是100%显示，请按键盘ctrl+0恢复100%显示标准，以防页面显示错乱！')
  }
}
 
//阻止pc端浏览器缩放js代码
//由于浏览器菜单栏属于系统软件权限，没发控制，我们着手解决ctrl/cammond + +/- 或 Windows下ctrl + 滚轮 缩放页面的情况，只能通过js来控制了
 // jqeury version
$(document).ready(function () {
  // chrome 浏览器直接加上下面这个样式就行了，但是ff不识别
  $('body').css('zoom', 'reset');
  $(document).keydown(function (event) {
    //event.metaKey mac的command键
    if ((event.ctrlKey === true || event.metaKey === true)&& (event.which === 61 || event.which === 107 || event.which === 173 || event.which === 109 || event.which === 187  || event.which === 189)){
      event.preventDefault();
    }
  });
  $(window).bind('mousewheel DOMMouseScroll', function (event) {
    if (event.ctrlKey === true || event.metaKey) {
       event.preventDefault();
    }
  });
});
</script>