通过使用此模块，只需将鼠标悬停在浏览器中，即可快速查看DOM元素的属性。基本上它是一个即时检查器。

    将鼠标悬停在 DOM 元素上会显示其属性

    1. (function SpyOn() {
    3.   const _id = 'spyon-container',
    4.         _posBuffer = 3;
    6.   function init() {
    7.     document.body.addEventListener('mousemove', glide);
    8.     document.body.addEventListener('mouseover', show);
    9.     document.body.addEventListener('mouseleave', hide);
    10.   }
    12.   function hide(e) {
    13.     document.getElementById(_id).style.display = 'none';
    14.   }
    16.   function show(e) {
    17.     const spyContainer = document.getElementById(_id);
    18.     if (!spyContainer) {
    19.       create();
    20.       return;
    21.     }
    22.     if (spyContainer.style.display !== 'block') {
    23.       spyContainer.style.display = 'block';
    24.     }
    25.   }
    27.   function glide(e) {
    28.     const spyContainer = document.getElementById(_id);
    29.     if (!spyContainer) {
    30.       create();
    31.       return;
    32.     }
    33.     const left = e.clientX + getScrollPos().left + _posBuffer;
    34.     const top = e.clientY + getScrollPos().top + _posBuffer;
    35.     spyContainer.innerHTML = showAttributes(e.target);
    36.     if (left + spyContainer.offsetWidth > window.innerWidth) {
    37.       spyContainer.style.left = left - spyContainer.offsetWidth + 'px';
    38.     } else {
    39.       spyContainer.style.left = left + 'px';
    40.     }
    41.     spyContainer.style.top = top + 'px';
    42.   }
    44.   function getScrollPos() {
    45.     const ieEdge = document.all ? false : true;
    46.     if (!ieEdge) {
    47.       return {
    48.         left : document.body.scrollLeft,
    49.         top : document.body.scrollTop
    50.       };
    51.     } else {
    52.       return {
    53.         left : document.documentElement.scrollLeft,
    54.         top : document.documentElement.scrollTop
    55.       };
    56.     }
    57.   }
    59.   function showAttributes(el) {
    60.     const nodeName = `<span style="font-weight:bold;">${el.nodeName.toLowerCase()}</span><br/>`;
    61.     const attrArr = Array.from(el.attributes);
    62.     const attributes = attrArr.reduce((attrs, attr) => {
    63.       attrs += `<span style="color:#ffffcc;">${attr.nodeName}</span>="${attr.nodeValue}"<br/>`;
    64.       return attrs;
    65.     }, '');
    66.     return nodeName + attributes;
    67.   }
    69.   function create() {
    70.     const div = document.createElement('div');
    71.     div.id = _id;
    72.     div.setAttribute('style', `
    73.       position: absolute;
    74.       left: 0;
    75.       top: 0;
    76.       width: auto;
    77.       height: auto;
    78.       padding: 10px;
    79.       box-sizing: border-box;
    80.       color: #fff;
    81.       background-color: #444;
    82.       z-index: 100000;
    83.       font-size: 12px;
    84.       border-radius: 5px;
    85.       line-height: 20px;
    86.       max-width: 45%;
    87.       `
    88.     );
    89.     document.body.appendChild(div);
    90.   }
    92.   init();
    94. })();