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前端上传图片预览

转成blob 预览

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input id="inputFile" type="file" accept="image/*">
<img src="" id="previewImage" alt="图片预览">
<script>
    const $ = document.getElementById.bind(document);
    const $inputFile = $('inputFile');
    const $previewImage = $('previewImage');
    $inputFile.addEventListener('change', function(e) {
        const file = this.files[0];
        console.log(e)
        console.log(file)
        $previewImage.src = file ? URL.createObjectURL(file) : '';
    }, this);
</script>
</body>
</html>

转换成base64预览
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input id="inputFile" type="file" accept="image/*">
<img src="" id="previewImage" alt="图片预览">
<script>
    const $ = document.getElementById.bind(document);
    const $inputFile = $('inputFile');
    const $previewImage = $('previewImage');
    $inputFile.addEventListener('change', function() {
        const file = this.files[0];
        const reader = new FileReader();
        console.log(reader)
        reader.addEventListener('load', function() {
            console.log(reader)
            $previewImage.src = reader.result;
        }, false);

        if(file) {
            reader.readAsDataURL(file);
        }
    }, false)
</script>
</body>
</html>

图片转base64 (url 包含blob)

 static imageToBase64(imgUrl) {
        return new Promise((resolve, reject) => {
            var imgFile = new FileReader();
            imgFile.readAsDataURL(imgUrl);
            imgFile.onload = function () {
                var imgData = this.result; //base64数据
                resolve(imgData)

            }

        })


    }

查看全文

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原文地址：https://www.cnblogs.com/aqigogogo/p/11775381.html