dropzone.js api

var myDropzone = new Dropzone("#my-dropzone", {
    url: "/upload",
    maxFilesize: 2, // MB
    acceptedFiles: "image/*",
    init: function() {
        this.on("addedfile", function(file) {
            console.log("File added: ", file);
        });
    }
});

myDropzone.on("error", function(file, errorMessage) {
    alert("Error uploading file: " + errorMessage);
});

<form action="/upload" class="dropzone" id="my-dropzone">
    <div class="fallback">
        <input name="file" type="file" multiple />
    </div>
</form>

var myDropzone = new Dropzone("#my-dropzone", {
    url: "/upload",
    maxFilesize: 2, // 最大文件大小为2MB
    acceptedFiles: "image/jpeg,image/png", // 只接受JPEG和PNG格式的图片
});