兼容IE8实现页面添加水印

参考文章：https://gitee.com/zhongjyuan/codes/qfeorbcy84nwikl63h7am35

本文主要参照以上文章的代码，在其基础上解决在本项目下出现的布局被影响和改变文字大小显示不全的问题。

// 水印
(function (watermark) {
    window.watermarkdivs = [];
    // 加载水印
    var loadMark = function (settings) {
        var defaultSettings = {
            watermark_txt: "",
            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: 0,//水印行数
            watermark_cols: 0,//水印列数
            watermark_x_space: 40,//水印x轴间隔
            watermark_y_space: 30,//水印y轴间隔
            watermark_font: '微软雅黑',//水印字体
            watermark_color: '#FF7F24',//水印字体颜色
            watermark_fontsize: '32px',//水印字体大小
            watermark_alpha: 0.3,//水印透明度，要求设置在大于等于0.003
            watermark_width: 240,//水印宽度
            watermark_height: 70,//水印长度
            watermark_angle: 15//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];
            }
        }

        if (window.watermarkdivs && window.watermarkdivs.length > 0) {
            document.body.removeChild(document.getElementById("otdivid"));
            window.watermarkdivs = [];
        }

        //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);
        // var page_height = Math.max(document.body.scrollTop,document.body.clientHeight);

        // 创建文档碎片
        var oTemp = document.createDocumentFragment();
        //创建水印外壳div
        var otdiv = document.getElementById("otdivid");

        if (!otdiv) {
            otdiv = document.createElement('div');
            otdiv.id = "otdivid";
            otdiv.style.pointerEvents = "none";
            document.body.appendChild(otdiv);
        }

        //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');
                var oText = document.createTextNode(defaultSettings.watermark_txt);
                mask_div.appendChild(oText);
                // 设置水印相关属性start
                mask_div.id = 'mask_div' + i + j;
                mask_div.onselectstart = "return false";
                //设置水印div倾斜显示
                mask_div.style.filter = "progid:DXImageTransform.Microsoft.Matrix(sizingMethod='auto expand', M11=0.96593, M12=0.25882, M21=-0.25882, M22=0.96593) progid:DXImageTransform.Microsoft.Alpha(opacity=15)";
                //逆时针旋转45度：progid:DXImageTransform.Microsoft.Matrix(sizingMethod='auto expand', M11=0.70710678118655, M12=0.70710678118655, M21=-0.70710678118655, M22=0.70710678118655);
                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 = "fixed";
                //选不中

                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.lineHeight = 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";
                //设置水印相关属性end
                //附加到文档碎片中
                otdiv.appendChild(mask_div);
                otdiv.style.cursor = "default";


                window.watermarkdivs.push(otdiv); //控制页面大小变化时水印字体
            };
        };
        //一次性添加到document中
        document.body.appendChild(oTemp);
    };

    watermark.init = function (settings) {
        window.onload = function () {
            loadMark(settings);
        };
        window.onresize = function () {
            loadMark(settings);
        };
    };

    watermark.load = function (settings) {
        loadMark(settings);
    };

})(window.watermark = {});

/*
 * Pointer Events Polyfill: Adds support for the style attribute
 * "pointer-events: none" to browsers without this feature (namely, IE).
 * (c) 2013, Kent Mewhort, licensed under BSD. See LICENSE.txt for details.
 */

// constructor
function PointerEventsPolyfill(options) {
    // set defaults
    this.options = {
        selector: '*',
        mouseEvents: ['click', 'dblclick', 'mousedown', 'mouseup'],
        usePolyfillIf: function () {
            // if (navigator.appName == 'Microsoft Internet Explorer')
            // {
            /* jshint ignore:start */
            var agent = navigator.userAgent;
            // if (agent.match(/MSIE ([0-9]{1,}[\.0-9]{0,})/) != null) {
            //     var version = parseFloat(RegExp.jQ1);
            //     if (version < 11)
            return true;
            // }
            /* jshint ignore:end */
            // }
            // return false;
        }
    };
    if (options) {
        var obj = this;
        $.each(options, function (k, v) {
            obj.options[k] = v;
        });
    }

    if (this.options.usePolyfillIf())
        this.register_mouse_events();
}


/**
 * singleton initializer
 *
 * @param   {object}    options     Polyfill options.
 * @return  {object}    The polyfill object.
 */

PointerEventsPolyfill.initialize = function (options) {
    /* jshint ignore:start */
    if (PointerEventsPolyfill.singleton == null)
        PointerEventsPolyfill.singleton = new PointerEventsPolyfill(options);
    /* jshint ignore:end */
    return PointerEventsPolyfill.singleton;
};


/**
 * handle mouse events w/ support for pointer-events: none
 */
PointerEventsPolyfill.prototype.register_mouse_events = function () {
    // register on all elements (and all future elements) matching the selector
	$(document).on(
	    this.options.mouseEvents.join(' '),
	    this.options.selector,
	    function (e) {
	        if ($(this).css('pointerEvents') == 'none') {
	
	            // peak at the element below
	            var origDisplayAttribute = $(this).css('display');
	            $(this).css('display', 'none');
	
	            var underneathElem = document.elementFromPoint(
	                e.clientX,
	                e.clientY);
	
	            if (origDisplayAttribute)
	                $(this)
	                    .css('display', origDisplayAttribute);
	            else
	                $(this).css('display', '');
	
	            // fire the mouse event on the element below
	            e.target = underneathElem;
	            $(underneathElem).trigger(e);
	            return false;
	        }
	        return true;
	    });
};

调用代码如下：

$(function () {
	if(USERNAME) { // USERNAME为我传递的水印
		watermark.load({ watermark_txt: USERNAME });
		PointerEventsPolyfill.initialize({});		
	}
});

效果图如下：