Html使用JS给页面加水印

(function(watermark){
	window.watermarkdivs = [];
	// 加载水印
	var loadMark = function(settings) {
			var defaultSettings={
				watermark_txt:"text",
				watermark_id:"watermark",//生成水印的DOM节点的ID值
				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:100,//水印x轴间隔
				watermark_y_space:50,//水印y轴间隔
				watermark_color:'#3e8ebd',//水印字体颜色
				watermark_alpha:0.5,//水印透明度，要求设置在大于等于0.005
				watermark_fontsize:'18px',//水印字体大小
				watermark_font:'微软雅黑',//水印字体
				watermark_width:150,//水印宽度
				watermark_height:100,//水印长度
				watermark_angle:15,//水印倾斜度数
				watermark_bg_alpha:0.5 //加透明度导致隐形水印无法读取
			};
			//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.getElementById(defaultSettings.watermark_id).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.getElementById(defaultSettings.watermark_id).scrollHeight,document.getElementById(defaultSettings.watermark_id).clientHeight);
//			var page_height = Math.max(document.body.scrollHeight,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.getElementById(defaultSettings.watermark_id).appendChild(otdiv)
//				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);
                    // 设置一张水印相关属性start
                    mask_div.id = 'mask_div' + i + j;
					//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";
					//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.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";
                    //设置一张水印相关属性end
                    //附加到文档碎片中
                    otdiv.appendChild(mask_div);

                    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tab_a_64
			document.getElementById(defaultSettings.watermark_id).appendChild(oTemp)
//			document.body.appendChild(oTemp);
		};
	
		watermark.load = function(settings) {
			window.onload = function() {
				loadMark(settings);
			};
			window.onresize = function() {
				loadMark(settings);
			};
		};
	
})(window.watermark = {});

使用：

<script src="watermark.js"></script>
<script>
    watermark.load({ watermark_txt: 'test', watermark_id: 'id'});
</script>

<div id="id"></div>