前端打印dom以及打印css设置

方法一

      const printWindow = window.open()
      printWindow.document.write(document.querySelector('#printBox').innerHTML)
      printWindow.print()
      printWindow.close()

方法二

print.js

// 打印类属性、方法定义
/* eslint-disable */
const Print = function(dom, options) {
  if (!(this instanceof Print)) return new Print(dom, options)

  this.options = this.extend(
    {
      noPrint: '.no-print',
    },
    options
  )

  if (typeof dom === 'string') {
    this.dom = document.querySelector(dom)
  } else {
    this.isDOM(dom)
    this.dom = this.isDOM(dom) ? dom : dom.$el
  }

  this.init()
}
Print.prototype = {
  init: function() {
    var content = this.getStyle() + this.getHtml()
    this.writeIframe(content)
  },
  extend: function(obj, obj2) {
    for (var k in obj2) {
      obj[k] = obj2[k]
    }
    return obj
  },

  getStyle: function() {
    var str = '',
      styles = document.querySelectorAll('style,link')
    for (var i = 0; i < styles.length; i++) {
      str += styles[i].outerHTML
    }
    str += '<style>' + (this.options.noPrint ? this.options.noPrint : '.no-print') + '{display:none;}</style>'

    return str
  },

  getHtml: function() {
    var inputs = document.querySelectorAll('input')
    var textareas = document.querySelectorAll('textarea')
    var selects = document.querySelectorAll('select')

    for (var k = 0; k < inputs.length; k++) {
      if (inputs[k].type == 'checkbox' || inputs[k].type == 'radio') {
        if (inputs[k].checked == true) {
          inputs[k].setAttribute('checked', 'checked')
        } else {
          inputs[k].removeAttribute('checked')
        }
      } else if (inputs[k].type == 'text') {
        inputs[k].setAttribute('value', inputs[k].value)
      } else {
        inputs[k].setAttribute('value', inputs[k].value)
      }
    }

    for (var k2 = 0; k2 < textareas.length; k2++) {
      if (textareas[k2].type == 'textarea') {
        textareas[k2].innerHTML = textareas[k2].value
      }
    }

    for (var k3 = 0; k3 < selects.length; k3++) {
      if (selects[k3].type == 'select-one') {
        var child = selects[k3].children
        for (var i in child) {
          if (child[i].tagName == 'OPTION') {
            if (child[i].selected == true) {
              child[i].setAttribute('selected', 'selected')
            } else {
              child[i].removeAttribute('selected')
            }
          }
        }
      }
    }

    return this.dom.outerHTML
  },

  writeIframe: function(content) {
    var w,
      doc,
      iframe = document.createElement('iframe'),
      f = document.body.appendChild(iframe)
    iframe.id = 'myIframe'
    //iframe.style = "position:absolute;width:0;height:0;top:-10px;left:-10px;";
    iframe.setAttribute('style', 'position:absolute;width:0;height:0;top:-10px;left:-10px;')
    w = f.contentWindow || f.contentDocument
    doc = f.contentDocument || f.contentWindow.document
    doc.open()
    doc.write(content)
    doc.close()
    var _this = this
    iframe.onload = function() {
      _this.toPrint(w)
      setTimeout(function() {
        document.body.removeChild(iframe)
      }, 100)
    }
  },

  toPrint: function(frameWindow) {
    try {
      setTimeout(function() {
        frameWindow.focus()
        try {
          if (!frameWindow.document.execCommand('print', false, null)) {
            frameWindow.print()
          }
        } catch (e) {
          frameWindow.print()
        }
        frameWindow.close()
      }, 10)
    } catch (err) {
      console.log('err', err)
    }
  },
  isDOM:
    typeof HTMLElement === 'object'
      ? function(obj) {
          return obj instanceof HTMLElement
        }
      : function(obj) {
          return obj && typeof obj === 'object' && obj.nodeType === 1 && typeof obj.nodeName === 'string'
        },
}
const MyPlugin = {}
MyPlugin.install = function(Vue, options) {
  // 4. 添加实例方法
  Vue.prototype.$print = Print
}
export default MyPlugin

在main.js注册插件

// 注册打印插件
import print from '@/plugin/print/print.js'
Vue.use(print)

在页面中使用

const dom = document.querySelector('#printBox')
this.$print(dom)

打印样式

export function setStyle (direction) {
  const styleNode = document.createElement('style')
  styleNode.setAttribute('id', 'print-style')
  styleNode.setAttribute('type', 'text/css')
  // styleNode.innerHTML = `
  //   @media print {
  //       @page {
  //           size: A4 ${direction};
  //           margin: 3mm;
  //       }
  //   }
  //   `
  styleNode.innerHTML = `
    @media print {
        @page {
            margin: 3mm;
        }
    }
    `
  window.document.head.appendChild(styleNode)
}
export function removeStyle () {
  const styleNode = document.querySelector('#print-style')
  window.document.head.removeChild(styleNode)
}

css设置

针对打印样式进行设置，这里要用到媒体查询，字体一般用pt单位，宽高和间距一般用物理单位cm或mm

@media print {
    html,body {
        //A4默认为210mm*287mm
        width:210mm
        height:297mm
    }
    .page{
        font-size:10pt;
        width:initial;
    }
    .page .part2 td{
        height:1cm;
    }
   　@page {
　　　　 size:landscape; //portrait纵向 landscape横向
      　　 margin:2mm;//设置打印出来的页面外边距
    }
/* 告诉浏览器在渲染它时不要对框进行颜色或样式调整 */
        * {
          -webkit-print-color-adjust: exact !important;
          -moz-print-color-adjust: exact !important;
          -ms-print-color-adjust: exact !important;
          print-color-adjust: exact !important;
        }
  .part2 {
      page-break-inside: avoid;//这样设置能保证表格每一行不会被强行分割
      page-break-before: always;//强制分页
  }

}