前端上传图片并显示

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>图片上传</title>
</head>
<body>
    <!-- 要将父布局的position设置为relative,父布局将无法包裹input -->
    <div style="position: relative;">
        <!--设置input的position为absolute,使其不按文档流排版,并设置其包裹整个布局 -->
        <!-- 设置opactity为0,使input变透明 -->
        <!-- 只接受jpg,gif和png格式 -->
        <input id="upload-input" style="position: absolute; top: 0; bottom: 0; left: 0;right: 0; opacity: 0;" type="file" accept="image/gif, image/jpg, image/png" onchange="showImg(this)" multiple />
        <!-- 自定义按钮效果 -->
        <div style="text-align: top">
            <span style="font-size: 12px;">上传文件:</span>
            <img id="upload" src="./upload.png" style=" 40px; height: 40px; vertical-align: middle;" />
        </div>
    </div>
    <div id="imgContainer" style="margin-top: 10px;"></div>
</body>
<script type="text/javascript">
    function showImg(obj) {
        var files = obj.files
        // document.getElementById("imgContainer").innerHTML = getImgsByUrl(files)
        getImgsByFileReader(document.getElementById("imgContainer"), files)
    }

    // 使用window.URL.createObjectURL(file)读取file实例并显示图片
    function getImgsByUrl(files) {
        var elements = ''
        for (var i = 0; i < files.length; i++) {
            var url = window.URL.createObjectURL(files[i])
            elements += "<img src='"+ url + "' style=' 40px; height: 40px; vertical-align: middle; margin-right: 5px;' />"
        }
        return elements
    }

    // 使用FileReader读取file实例并显示图片
    function getImgsByFileReader(el, files) {
        for (var i = 0; i < files.length; i++) {
            let img = document.createElement('img')
            img.setAttribute('style', ' 40px; height: 40px; vertical-align: middle; margin-right: 5px;')
            el.appendChild(img)
            var reader = new FileReader()
            reader.onload = function(e) {
                img.src = e.target.result
            }
            reader.readAsDataURL(files[i]) 
        }
    }
</script>
</html>

  

原文地址:https://www.cnblogs.com/navysummer/p/12848749.html