The readAsBinaryString method is used to start reading the contents of the specified Blob or File. When the read operation is finished, the readyState becomes DONE, and the loadend is triggered. At that time, the result attribute contains the raw binary data from the file.
The readAsDataURL method is used to read the contents of the specified Blob or File. When the read operation is finished, the readyState becomes DONE, and the loadend is triggered. At that time, the result attribute contains the data as a URL representing the file's data as a base64 encoded string.
The readAsText method is used to read the contents of the specified Blob or File. When the read operation is complete, the readyState is changed to DONE, the loadend is triggered, and the result attribute contains the contents of the file as a text string.
Returns the file's contents. This property is only valid after the read operation is complete, and the format of the data depends on which of the methods was used to initiate the read operation.
The FormData object lets you compile a set of key/value pairs to send using XMLHttpRequest. It is primarily intended for use in sending form data, but can be used independently from forms in order to transmit keyed data. The transmitted data is in the same format that the form's submit() method would use to send the data if the form's encoding type were set to multipart/form-data.
The File.lastModifiedDateread-only property returns the last modified date of the file. Files without a known last modified date returns the current date .
The FileReader interface's readAsArrayBuffer() method is used to start reading the contents of a specified Blob or File. When the read operation is finished, the readyState becomes DONE, and the loadend is triggered. At that time, the result attribute contains an ArrayBuffer representing the file's data.