基于JavaScript编写一个图片转PDF转换器

<div class="container">

</div>

*,
*:after,
*:before{
 -webkit-box-sizing: border-box;
 -moz-box-sizing: border-box;
 -ms-box-sizing: border-box;
 box-sizing: border-box;
}

body{
 font-family: arial;
 font-size: 16px;
 margin: 0;
 background: linear-gradient(133deg, #4abeb2, #3c57d2);
 color: #000;
 display: flex;
 align-items: center;
 justify-content: center;
 min-height: 100vh;
}

.container{
  background: white;
  width: 450px;
  padding: 30px;
  border-radius: 5px;
}

<img id="showImg" src="images/img.png">

#showImg{
 display: block;
 margin: 0 auto;
 max-width: 400px;
 min-height: 200px;
 background: #174353;
 border-radius: 5px;
}

 <div class="button">
   <div class="upload">
    <input type="file" onChange="loadFile(event)" name="" accept=".png, .jpg, .jpeg">
    上传图片
  </div>
	<button onClick="pdfDown()">下载PDF</button>
</div>

input{
 position: absolute;
 left: 0;
 top: 0;
 width: 100%;
 height: 100%;
 opacity: 0;
 z-index: 1;
}

.button{
  display: flex;
}
button,.upload{
 width: 220px;
 margin: 50px 20px 10px 20px ;
 text-align: center;
 position: relative;
 padding: 10px 5px;
 font-size: 17px;
 outline: none;
 color: #fff;
 border: none;
 background-color: #023780;
 border-radius: 5px;
 display: block;
}

.upload{
 background: #a74901;
}

var newImage, showImg;
function loadFile(event) {
  showImg = document.getElementById('showImg');
  showImg.src = URL.createObjectURL(event.target.files[0]);

  newImage = document.createElement('img');
  newImage.src = URL.createObjectURL(event.target.files[0]);

  showImg.onload = function() {
    URL.revokeObjectURL(showImg.src) 
}
};

function pdfDown(){
  console.log(newImage)
  var doc = new jsPDF();
  doc.addImage(newImage,10,10);
  doc.save('ImgToPDF.pdf')
}