原文：https://www.cnblogs.com/Miracle-ZLZ/p/9340249.html
此方法可以给整个页面或某个div添加水印效果。
1、普通使用方式：
$(document).ready(function() {
var watermark_txt = "测试效果" + getDate();
watermark({"watermarl_element":"watermark-wrapper", "watermark_txt":watermark_txt});
});注：watermark-wrapper是div的id名称。
2、如果项目中有ajax请求，等待所有ajax请求结束后再去加载，这样可以避免div存在滚动条时水印显示不全
$(document).ready(function() {
var watermark_txt = "测试效果" + getDate();
$.when($.ajax(), $.ajax()).then(function(){
watermark({"watermarl_element":"watermark-wrapper", "watermark_txt":watermark_txt});
});
});3、效果图：
4、代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>页面添加水印</title>
<script src="js/jquery.js"></script>
<style>
.watermark-wrapper{
height: 1000px;
}
</style>
</head>
<body>
<div id="watermark-wrapper" class="watermark-wrapper">
</div>
</body>
<script>
$(document).ready(function() {
var watermark_txt = "测试效果" + getDate();
watermark({"watermarl_element":"watermark-wrapper", "watermark_txt":watermark_txt});
});
function watermark(settings) {
//默认设置
var defaultSettings={
watermarl_element:"body",
watermark_txt:"",
watermark_x:10,//水印起始位置x轴坐标
watermark_y:10,//水印起始位置Y轴坐标
watermark_rows:2000,//水印行数
watermark_cols:2000,//水印列数
watermark_x_space:50,//水印x轴间隔
watermark_y_space:50,//水印y轴间隔
watermark_color:'#d7d7d7',//水印字体颜色
watermark_alpha:0.5,//水印透明度
watermark_fontsize:'15px',//水印字体大小
watermark_font:'微软雅黑',//水印字体
watermark_width:500,//水印宽度
watermark_height:50,//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];
}
}
}
var oTemp = document.createDocumentFragment();
var maskElement=document.getElementById(defaultSettings.watermarl_element) || document.body;
//获取页面最大宽度
var page_width = Math.max(maskElement.scrollWidth,maskElement.clientWidth);
//获取页面最大高度
var page_height = Math.max(maskElement.scrollHeight,maskElement.clientHeight,maskElement.scrollTop);
//水印数量自适应元素区域尺寸
defaultSettings.watermark_cols=Math.ceil(page_width/(defaultSettings.watermark_x_space+defaultSettings.watermark_width));
defaultSettings.watermark_rows=Math.ceil(page_height/(defaultSettings.watermark_y_space+defaultSettings.watermark_height));
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));
mask_div.innerHTML=(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 = "1029"; // 9999
// pointer-events:none 让水印不遮挡页面的点击事件
mask_div.style.pointerEvents='none';
// 设置边框
// mask_div.style.border="solid #eee 1px";
// 兼容IE9以下的透明度设置
mask_div.style.filter="alpha(opacity=50)";
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);
};
};
maskElement.appendChild(oTemp);
}
function getDate() {
var d = new Date();
var year = d.getFullYear() >= 10 ? d.getFullYear() : ('0'+d.getFullYear());
var month = d.getMonth()+1 >= 10 ? d.getMonth()+1 : ('0'+d.getMonth()+1);
var day = d.getDate() >= 10 ? d.getDate() : ('0'+d.getDate());
var hour = d.getHours() >= 10 ? d.getHours() : ('0'+d.getHours());
var minute = d.getMinutes() >= 10 ? d.getMinutes() : ('0'+d.getMinutes());
var second = d.getSeconds() >= 10 ? d.getSeconds() : ('0'+d.getSeconds());
return year+"-"+month+"-"+day+" "+hour+":"+minute+":"+second;
}
</script>
</html>
