Event binding on file upload

2019-06-21 20:47发布

Is there a way to bind an event when a user selects a file to upload and clicks on "open", I want to trigger the event when the user has clicked on open.

回答1:

In that scenario, the change event will be fired.

If you have this HTML:

<input type="file" id="fileInput" />

Then use this JS:

window.onload = function () {
    document.getElementById("fileInput").onchange = function () {
        // this.value
    };
};

(with the option of using addEventListener/attachEvent instead of setting the onclick property)

Inside the handler, you can use this.value to get the file selected.

Of course, with jQuery, you can use:

$(document).ready(function () {
    $("#fileInput").on("change", function () {
        // this.value OR $(this).val()
    });
});

NOTE: The window.onload and $(document).ready handlers are used to make sure the element is available. Of course, this event can occur much later than actually necessary, since they wait for all elements on the page to be ready (and window.onload waits even longer for things like images to be loaded). An option is to bind the onchange handler immediately after the element on the page or at the end of the <body>.