JavaScript: The Definitive Guide, Fourth Edition

Name

FileUpload — a file upload field for form input

Availability

JavaScript 1.0 Inherits from Input, HTMLElement

Synopsis

                  form.name
                  form.elements[i]

Properties

FileUpload inherits properties from Input and HTMLElement and defines or overrides the following:

value [ JavaScript 1.1]

A read-only string that specifies the filename entered by the user into the FileUpload object. The user may enter a filename either by typing it directly or by using the directory browser associated with the FileUpload object.

To prevent malicious programs from uploading arbitrary files from the client, this property may not be set by JavaScript code. Similarly, the value attribute of the <input> tag does not specify the initial value for this property.

Methods

FileUpload inherits methods from Input and HTMLElement.

Event Handlers

FileUpload inherits event handlers from Input and HTMLElement and defines or overrides the following:

onchange

Invoked when the user changes the value in the FileUpload element and moves the keyboard focus elsewhere. This event handler is not invoked for every keystroke in the FileUpload element, but only when the user completes an edit.

HTML Syntax

A FileUpload element is created with a standard HTML <input> tag:

<form enctype="multipart/form-data"
      method="post">         // Required attributes
    ...
  <input
    type="file"              // Specifies that this is a FileUpload element
    [ name="name" ]          // A name you can use later to refer to this element
                             // Specifies the name property
    [ size="integer" ] // How ...