使用HTML5的File实现base64和图片的互转

分手后的思念是犯贱 2022-11-21 03:36 126阅读 0赞

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
      <title>简单的html5 File测试 for pic2base64</title>
      <style>
      </style>
      <script>
        window.onload = function(){ 
          var input = document.getElementById("demo_input");
          var result= document.getElementById("result");
          var img_area = document.getElementById("img_area");
          if ( typeof(FileReader) === 'undefined' ){ 
            result.innerHTML = "抱歉，你的浏览器不支持 FileReader，请使用现代浏览器操作！";
            input.setAttribute( 'disabled','disabled' );
          } else { 
            input.addEventListener( 'change',readFile,false );}
        }
        function readFile(){ 
          var file = this.files[0];
    //这里我们判断下类型如果不是图片就返回 去掉就可以上传任意文件
          if(!/image\/\w+/.test(file.type)){ 
            alert("请确保文件为图像类型");
            return false;
          }
          var reader = new FileReader();
          reader.readAsDataURL(file);
          reader.onload = function(e){ 
            result.innerHTML = '<img src="'+this.result+'" alt=""/>';
            img_area.innerHTML = '<div class="sitetip">图片img标签展示：</div><img src="'+this.result+'" alt=""/>';
          }
        }
      </script>
    </head>
    <body>
    <input type="file" value="sdgsdg" id="demo_input" />
    <textarea id="result" rows=30 cols=300></textarea>
    <p id="img_area"></p>
    </body>
    </html>

实际效果：选择文件上传后会将图片转换成base64,在转换成图片  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzA4NTc5Nw_size_16_color_FFFFFF_t_70_pic_center]

[参考链接][Link 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzA4NTc5Nw_size_16_color_FFFFFF_t_70_pic_center]: /images/20221120/f217947302f142f2b87d0f07ba65fcf3.png
[Link 1]: https://www.jb51.net/html5/95473.html