js 页面添加水印，防止用户控制台篡改，删除

//function (settings) {

var defaultSettings = {
  watermark_txt: "text",
  watermark_x: 20, //水印起始位置x轴坐标
  watermark_y: 20, //水印起始位置Y轴坐标
  watermark_rows: 30, //水印行数
  watermark_cols: 20, //水印列数
  watermark_x_space: 100, //水印x轴间隔
  watermark_y_space: 20, //水印y轴间隔
  watermark_color: '#aaa', //水印字体颜色
  watermark_alpha: 0.1, //水印透明度
  watermark_fontsize: '16px', //水印字体大小
  watermark_font: '微软雅黑', //水印字体
  watermark_width: 260, //水印宽度
  watermark_height: 80, //水印长度
  watermark_angle: 15 //水印倾斜度数
};
Object.assign(defaultSettings, settings);
var oTemp = document.createDocumentFragment();
//获取页面最大宽度
var p_width = Math.max(document.body.scrollWidth, document.body.clientWidth);
var cutWidth = p_width * 0.0150;
var page_width = p_width - cutWidth;
//获取页面最大高度
var page_height = Math.max(document.body.scrollHeight, document.body.clientHeight);

// var page_height = document.body.scrollHeight+document.body.scrollTop;
//如果将水印列数设置为0，或水印列数设置过大，超过页面最大宽度，则重新计算水印列数和水印x轴间隔

if (defaultSettings.watermark_cols === 0 || (parseInt(defaultSettings.watermark_x + defaultSettings.watermark_width * defaultSettings.watermark_cols + defaultSettings.watermark_x_space * (defaultSettings.watermark_cols - 1)) > page_width)) {
  defaultSettings.watermark_cols = parseInt((page_width - defaultSettings.watermark_x + defaultSettings.watermark_x_space) / (defaultSettings.watermark_width + defaultSettings.watermark_x_space));
  defaultSettings.watermark_x_space = parseInt((page_width - defaultSettings.watermark_x - defaultSettings.watermark_width * defaultSettings.watermark_cols) / (defaultSettings.watermark_cols - 1));
}
//如果将水印行数设置为0，或水印行数设置过大，超过页面最大长度，则重新计算水印行数和水印y轴间隔

defaultSettings.watermark_rows = parseInt((defaultSettings.watermark_y_space + page_height - defaultSettings.watermark_y) / (defaultSettings.watermark_height + defaultSettings.watermark_y_space));
defaultSettings.watermark_y_space = parseInt(((page_height - defaultSettings.watermark_y) - defaultSettings.watermark_height * defaultSettings.watermark_rows) / (defaultSettings.watermark_rows - 1));
var x;
var y;

for (var i = 0; i < defaultSettings.watermark_rows; i++) {
  y = defaultSettings.watermark_y + (defaultSettings.watermark_y_space + defaultSettings.watermark_height) * i;
  for (var j = 0; j < defaultSettings.watermark_cols; j++) {
    x = defaultSettings.watermark_x + (defaultSettings.watermark_width + defaultSettings.watermark_x_space) * j;
    var mask_div = document.createElement('div');
    mask_div.id = 'mask_div' + i + j;
    mask_div.className = 'mask_div';
    mask_div.appendChild(document.createTextNode(defaultSettings.watermark_txt));
    //设置水印div倾斜显示
    mask_div.style.webkitTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
    mask_div.style.MozTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
    mask_div.style.msTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
    mask_div.style.OTransform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
    mask_div.style.transform = "rotate(-" + defaultSettings.watermark_angle + "deg)";
    mask_div.style.visibility = "";
    mask_div.style.position = "absolute";
    mask_div.style.left = x + 'px';
    mask_div.style.top = y + 'px';
    mask_div.style.overflow = "hidden";
    mask_div.style.zIndex = "9999";
    mask_div.style.pointerEvents = 'none'; //pointer-events:none 让水印不遮挡页面的点击事件
    mask_div.style.opacity = defaultSettings.watermark_alpha;
    mask_div.style.fontSize = defaultSettings.watermark_fontsize;
    mask_div.style.fontFamily = defaultSettings.watermark_font;
    mask_div.style.color = defaultSettings.watermark_color;
    mask_div.style.textAlign = "center";
    mask_div.style.width = defaultSettings.watermark_width + 'px';
    mask_div.style.height = defaultSettings.watermark_height + 'px';
    mask_div.style.display = "block";
    oTemp.appendChild(mask_div);
  };
};
var water_div = document.createElement('div');
    water_div.id = 'water_div';
    water_div.className = 'water_div';
    water_div.appendChild(oTemp)
document.body.appendChild(water_div);

} (```)

调用： 监听修改

watermark({watermark_txt: co.$cookie('usr-name')});

var options = { //监听属性
  attributes: true,
  childList: true,
  subtree: true,
  characterData: true,
  attributeOldValue: true
};

//监听水印dox变化
function addListener(){
  var mutationObserver = new MutationObserver(function(){
    var waterBox = document.querySelector('#water_div') || document.querySelector('.water_div');
    waterBox.remove()
    watermark({watermark_txt: _co._$cookie('usr-name')});
    mutationObserver.observe(document.querySelector('#water_div'), options);
  });
  mutationObserver.observe(document.querySelector('#water_div'), options);
  
  //如果只监听水印box,删除水印box也是会删除掉，所以还要监听外层box
  var mutationObserver1 = new MutationObserver(function(mo){
    if(mo[0].target.nodeName == 'BODY' && mo[0].previousSibling && mo[0].previousSibling.nodeName == '#text' && mo[0].removedNodes.length > 0 && mo[0].addedNodes.length == 0){
      watermark({watermark_txt: _co._$cookie('usr-name')});
      mutationObserver.observe(document.querySelector('#water_div'), options);
    }
  });
  mutationObserver1.observe(document.querySelector('#water_div').parentNode, options);
  
  //监听页面内容高度变化
  var mutationObserver2 = new MutationObserver(function(){
    var waterBox = document.querySelector('#water_div') || document.querySelector('.water_div');
    waterBox.remove()
  });
  mutationObserver2.observe(document.querySelector('.g-bd'), options);
}
addListener()