Js网页添加水印

import { debounce } from "./index"
const id = 'water-mark'

const setWaterMark = (content) => {
    if (document.getElementById(id) != null) document.body.removeChild(document.getElementById(id))
    const canvas = document.createElement('canvas')
    canvas.width = 300
    canvas.height = 150
    const ctx = canvas.getContext('2d')
    ctx.rotate((-20 * Math.PI) / 180)
    ctx.font = '14px normal'
    ctx.fillStyle = 'rgba(200, 200, 200, 0.30)'
    ctx.textBaseline = 'middle'
    ctx.textAlign = 'center'
    const contents = Array.isArray(content) ? content : [content]
    contents.forEach((item, index) => {
        ctx.fillText(item || "", canvas.width / 5, canvas.height / 2 + (index * 20))
    })
    const dom = document.createElement('div')
    dom.id = id
    dom.style.pointerEvents = 'none'
    dom.style.position = 'absolute'
    dom.style.top = '0px'
    dom.style.left = '0px'
    dom.style.zIndex = '9'
    dom.style.width = `${document.documentElement.clientWidth}px`
    dom.style.height = `${document.documentElement.clientHeight}px`
    dom.style.background = `url(${canvas.toDataURL('image/png')}) repeat`
    document.body.appendChild(dom)
}

export default (content) => {
    if (document.getElementById(id) == null) setWaterMark(content)
    window.onresize = debounce(() => setWaterMark(content))
}

import waterMark from '@/utils/waterMark.js'
waterMark("添加水印")
// 或多个
waterMark(["添加水印","添加水印"])