声明：该内容来自网友博客，本地进行了小改动，改动为以下两点：

1. 添加固定区域水印添加
2. 增加水印内容个数

话不多说，直接看代码:

function watermark(settings) {
    //默认设置
    var defaultSettings={
        watermark_txt:["添加水印1","添加水印2"],//默认值
        watermark_id:"body",
        watermark_x:0,//水印起始位置x轴坐标
        watermark_y:0,//水印起始位置Y轴坐标
        watermark_rows:7,//水印行数
        watermark_cols:6,//水印列数
        watermark_x_space:0,//水印x轴间隔
        watermark_y_space:0,//水印y轴间隔
        watermark_color:'#000000',//水印字体颜色
        watermark_alpha:0.05,//水印透明度
        watermark_fontsize:'14px',//水印字体大小
        watermark_fontWeight:'bold',//水印字体加粗
        watermark_font:'微软雅黑',//水印字体
        watermark_width:120,//水印宽度
        watermark_height:80,//水印长度
        watermark_angle:321//水印倾斜度数
    };
    //采用配置项替换默认值，作用类似jquery.extend
    if(arguments.length===1&&typeof arguments[0] ==="object" )
    {
        var src=arguments[0]||{};
        for(key in src)
        {
            if(src[key]&&defaultSettings[key]&&src[key]===defaultSettings[key])
                continue;
            else if(src[key])
                defaultSettings[key]=src[key];
        }
    }
    var oTemp = document.createDocumentFragment();
    //获取页面最大宽度
    var page_width = Math.max(document.body.scrollWidth,document.body.clientWidth);
    //获取页面最大长度
    var page_height = Math.max(document.body.scrollHeight,document.body.clientHeight);
    //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
    if (defaultSettings.watermark_rows == 0 ||
       (parseInt(defaultSettings.watermark_y 
    + defaultSettings.watermark_height * defaultSettings.watermark_rows 
    + defaultSettings.watermark_y_space * (defaultSettings.watermark_rows - 1)) 
    > page_height)) {
        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;
            for(var shui=0;shui<defaultSettings.watermark_txt.length;shui++){
				var para = document.createElement('br');    
            	mask_div.appendChild(document.createTextNode(defaultSettings.watermark_txt[shui]));
				mask_div.appendChild(para);
            }
            //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.border="solid #eee 1px";
            mask_div.style.opacity = defaultSettings.watermark_alpha;
            mask_div.style.fontSize = defaultSettings.watermark_fontsize;
            mask_div.style.fontWeight = defaultSettings.watermark_fontWeight;
            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);
        };
    };
    document.getElementById(defaultSettings.watermark_id).appendChild(oTemp);
}
watermark({ watermark_txt: ["添加水印1","添加水印2"],watermark_id:"bodys" })//传入动态水印内容