前言
是否遇到过,网站的内容需要防止别人随意截图流传?

是否遇到过,网页加上水印用户体验不好?

简介

    网页加水印的方式很多,加隐藏水印的方式也很多,但可能我们往往也只是想要个简易的隐藏式水印。

    怎样个隐藏法?就是肉眼在正常环境下,浅色(或纯白)背景下看不出什么水印痕迹。但只要经过特殊处理(亮度调低),就能把水印显现出来。具体实现看以下代码。

function watermark(settings) {

//默认设置
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:5,//水印行数
watermark_cols:5,//水印列数
watermark_x_space:10,//水印x轴间隔
watermark_y_space:90,//水印y轴间隔
watermark_color:'#000000',//水印字体颜色
watermark_alpha:0.005,//水印透明度
watermark_fontsize:'80px',//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:90,//水印长度
watermark_angle:25//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;
  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";
  //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.pointerEvents = "none";
  //mask_div.style.border="solid #eee 1px";
  mask_div.style.opacity = defaultSettings.watermark_alpha;
  mask_div.style.fontSize = defaultSettings.watermark_fontsize;
  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.body.appendChild(oTemp);
}
watermark({ watermark_txt:'hello'})