Detailed explanation of input type=file to select pictures and achieve preview effects-JS Tutorial-php.cn

Detailed explanation of input type=file to select pictures and achieve preview effects

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Release： 2018-01-02 16:00:29

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This article mainly brings you an example of selecting images with input type=file and achieving preview effects. The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor to take a look, I hope it can help everyone.

Through the tag, specify the type as file, which can provide file upload;

accept: You can choose the upload type, such as: just upload pictures, and there are no restrictions The image format is image/*;

multiple: specifies whether multiple files can be selected;

specifies that only pictures can be uploaded, and multiple files can be selected

<input type="file" accept="image/*" multiple="multiple"/>

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Of course , a direct input type=file can only select uploaded files/resources. If we need to achieve the preview effect on the current page after selecting the image, then we can achieve it in the following way

HTML code

<body>
  <p id="box">
    <img id="imgshow" src="" alt=""/>
  </p>
  <p id="pox">
    <input id="filed" type="file" accept="image/*"/>
  </p>
</body>

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css style file

<style>
    #box{
      width: 300px;
      height: 300px;
      border: 2px solid #858585;
    }
    #imgshow{
      width: 100%;
      height: 100%;
    }
    #pox{
      width: 70px;
      height: 24px;
      overflow: hidden;
    }
  </style>

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JS code

<script>
    //在input file内容改变的时候触发事件
    $('#filed').change(function(){
    //获取input file的files文件数组;
    //$('#filed')获取的是jQuery对象，.get(0)转为原生对象;
    //这边默认只能选一个，但是存放形式仍然是数组，所以取第一个元素使用[0];
      var file = $('#filed').get(0).files[0];
    //创建用来读取此文件的对象
      var reader = new FileReader();
    //使用该对象读取file文件
      reader.readAsDataURL(file);
    //读取文件成功后执行的方法函数
      reader.onload=function(e){
    //读取成功后返回的一个参数e，整个的一个进度事件
        console.log(e);
    //选择所要显示图片的img，要赋值给img的src就是e中target下result里面
    //的base64编码格式的地址
        $('#imgshow').get(0).src = e.target.result;
      }
    })
</script>

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*JQuery is used in the above js code, so the jQuery file must be introduced

Related recommendations:

File Control Select Picture Example Tutorial

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The input image will not be uploaded and displayed in time after selecting it

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