/** *网页加水印 svg 方式 * * @export * @param {*} [{ *   container = document.body, *   content = '请勿外传', *   width = '300px', *   height = '200px', *   opacity = '0.2', *   fontSize = '20px', *   zIndex = 1000 * }={}] */ function __waterDocumentSvg({  container = document.body,  content = '请勿外传',  width = '120px',  height = '200px',  opacity = '0.2',  fontSize = '20px',  zIndex = 0} = {}) {  const args = arguments[0];  const svgStr = `
     
      
       ${content}
      
     `;  const base64Url = `data:image/svg+xml;base64,${window.btoa(unescape(encodeURIComponent(svgStr)))}`;  const __wm = document.querySelector('.__wm');  const watermarkDiv = __wm || document.createElement("div");  const styleStr = `    position:absolute;    top:0;    left:0;    width:100%;    height:100%;    z-index:${zIndex};    pointer-events:none;    background-repeat:repeat;    background-image:url('${base64Url}')`;  watermarkDiv.setAttribute('style', styleStr);  watermarkDiv.classList.add('__wm');  if (!__wm) {    container.style.position = 'relative';    container.insertBefore(watermarkDiv, container.firstChild);  }  const MutationObserver = window.MutationObserver || window.WebKitMutationObserver;  if (MutationObserver) {    let mo = new MutationObserver(function () {      const __wm = document.querySelector('.__wm');      // 只在__wm元素变动才重新调用 __canvasWM      if ((__wm && __wm.getAttribute('style') !== styleStr) || !__wm) {        // 避免一直触发        mo.disconnect();        mo = null;        __waterDocumentSvg(JSON.parse(JSON.stringify(args)));      }    });    mo.observe(container, {      attributes: true,      subtree: true,      childList: true    })  }}        //onload时触发水印绘制    window.οnlοad=function(){        __waterDocumentSvg({content : "申继林"});    };