JS 实现系统打印的四种方式
一. JS 使用 window 的方法直接打印
下面是 window 打印的公共方法封装
// 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");
}
}
}
}
}
// 包裹要打印的元素
let outerHTML = this.wrapperRefDom(this.dom).outerHTML;
return outerHTML;
},
// 向父级元素循环，包裹当前需要打印的元素
// 防止根级别开头的 css 选择器不生效
wrapperRefDom: function (refDom) {
let prevDom = null;
let currDom = refDom;
// 判断当前元素是否在 body 中，不在文档中则直接返回该节点
if (!this.isInBody(currDom)) return currDom;
while (currDom) {
if (prevDom) {
let element = currDom.cloneNode(false);
element.appendChild(prevDom);
prevDom = element;
} else {
prevDom = currDom.cloneNode(true);
}
currDom = currDom.parentElement;
}
return prevDom;
},
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);
}
},
// 检查一个元素是否是 body 元素的后代元素且非 body 元素本身
isInBody: function (node) {
return node === document.body ? false : document.body.contains(node);
},
isDOM:
typeof HTMLElement === "object"
? function (obj) {
return obj instanceof HTMLElement;
}
: function (obj) {
return (
obj &&
typeof obj === "object" &&
obj.nodeType === 1 &&
typeof obj.nodeName === "string"
);
},
};
export default Print;
- 使用 window 的方法单个打印
<script setup>
// vue3.0写法
import Print from "@/utils/print.js";
const printBtn = () => {
const printBox = document.getElementById("printBox");
Print(printBox);
};
</script>
<template>
<div id="printBox">
<div class="content">
<img src="@/assets/logo.png" alt="" />
<div>我是打印盒子</div>
</div>
</div>
<button @click="printBtn">打印</button>
</template>
<style>
.content {
background: #e73535;
}
/* 解决背景色打印不出来得问题 */
@media print {
.content {
background: #e73535;
-webkit-print-color-adjust: exact;
}
}
</style>
- 分页打印
<script setup>
import { ref, reactive } from "vue";
import Print from "@/utils/print.js";
const printListBox = ref(null);
const num = ref('');
const list = reactive([]);
const creatDom = () => {
list.splice(0);
if (!num.value) return;
for (let i = 1; i <= num.value; i++) {
list.push(i);
}
};
const printBtn = () => {
Print(printListBox.value);
};
</script>
<template>
<div>使用window打印的方法 实现分页打印</div>
<div>
<input
type="number"
v-model="num"
@keyup.enter="creatDom"
placeholder="请输入你想生成的数量"
/>
<button @click="creatDom">确定</button>
</div>
<br />
<button v-show="list.length > 0" @click="printBtn">打印</button>
<br />
<br />
<div class="list" ref="printListBox">
<div class="content" v-for="item in list" :key="item">
<img src="@/assets/logo.png" alt="" />
<div>我是打印盒子{{ item }}</div>
<!-- 在你需要分页的位置加上 -->
<div style="page-break-after: always"></div>
</div>
</div>
</template>
<style>
.content {
background: #e73535;
color: #fff;
margin-bottom: 20px;
}
/* 解决背景色打印不出来得问题 */
@media print {
.content {
background: #e73535;
color: #fff;
margin-bottom: 20px;
-webkit-print-color-adjust: exact;
}
}
</style>
总结： 核心是第一个代码块中的打印方法封装 传入一个你要打印的 DOM 即可
二. JS 生成 PDF web 渲染 PDF 在 PDF 中打印
- 首先要引入
html2canvas和jspdf// 将页面 html 转换成图片 npm install html2canvas --save // 将图片生成 pdf npm install jspdf --save - 其次看下方代码
<script setup>
import html2Canvas from "html2canvas";
import JsPDF from "jspdf";
import { ref } from "vue";
const box = ref(null);
const createPdf = () => {
/**
* JsPDF参数
* 第一个参数： l：横向 p：纵向
* 第二个参数：测量单位（"pt"，"mm", "cm", "m", "in" or "px"） 需要啥用啥
* 第三个参数：可以是下面格式，默认为“a4” 如果您想使用自己的格式，只需将大小作为数字数组传递，例如[595.28, 841.89];
*/
// 定义一个pdf
const pdf = new JsPDF("", "px");
// 设置生成的PDF文档
pdf.setProperties({
title: "title",
subject: "打印sn标签",
author: "J",
keywords: "javascript, web, pdf, print",
creator: "creator",
});
// 使用 html2Canvas 画个canvas
html2Canvas(box.value).then((canvas) => {
const pageData = canvas.toDataURL("image/jpeg", 1);
pdf.addImage(pageData, "JPEG", 0, 0);
const blob = pdf.output("blob");
var blob_url = URL.createObjectURL(blob);
document.getElementById("iframeBox").src = blob_url;
});
};
</script>
<template>
<div>JS生成PDF</div>
<br />
<div>我们先来画一个盒子</div>
<br />
<div ref="box">
<div class="content">
<img src="@/assets/logo.png" alt="" />
<div>我是打印盒子</div>
</div>
</div>
<br />
<div>
<button @click="createPdf">点击打印试试</button>
</div>
<iframe id="iframeBox" src="" frameborder="0" ></iframe>
</template>
<style scoped>
.content {
width: 841px;
background: #e73535;
color: #fff;
}
#iframeBox {
width: 90vw;
height: 985px;
}
</style>
生成多页PDF的代码和教程以及其他操作就不贴了 有兴趣的马上看最下面的gitHub地址吧
https://github.com/552088072/vue3-print-demo
总结：前端生成PDF如果数据量少 还好 数据量大的话还是需要后端哦 超过100条 基本上就明显的有等待时间了 更多操作还是在github上把我demo下载下来看看
