此方法开箱即用，在vue项目中import即可。

例如：

//在vue组件中
import Watermark from '@/utils/watermark.js'//在methods中
Watermark.set({color:"",text:""})//设置水印Watermark.remove() //删除水印

const watermark = {}const id = '1.23452384164.123412415'const setWatermark = (option) => {if (document.getElementById(id) !== null) {document.body.removeChild(document.getElementById(id))}const can = document.createElement('canvas')can.width = 350can.height = 250const cans = can.getContext('2d')cans.rotate(-20 * Math.PI / 180)cans.font = '15px Vedana'cans.fillStyle = option.color||'rgba(200, 200, 200, 0.30)'cans.textAlign = 'left'cans.textBaseline = 'Middle'cans.fillText(option.text, 1, can.height)const div = document.createElement('div')div.id = iddiv.style.pointerEvents = 'none'div.style.top = '0'div.style.left = '0'div.style.position = 'fixed'div.style.zIndex = '100000'div.style.width = document.documentElement.clientWidth - 100 + 'px'div.style.height = document.documentElement.clientHeight - 100 + 'px'div.style.background = 'url(' + can.toDataURL('image/png') + ') left top repeat'return div
}// 该方法只允许调用一次
watermark.set = (option) => {const div = setWatermark(option)document.body.appendChild(div)// setInterval(() => {//   if (document.getElementById(id) === null) {//     id = setWatermark(str)//   }// }, 500)window.onresize = () => {const div = setWatermark(option)document.body.appendChild(div)}
}watermark.remove = () => {const obj = document.getElementById(id)if (obj != null) {obj.parentNode.removeChild(obj)}
}export default watermark