Javascript----File Operation
1. Function implementation core: FileSystemObject object
To implement file operation functions in javascript, we mainly rely on the FileSystemobject object.
2. FileSystemObject Programming
Programming using FileSystemObject object is very simple. Generally, you have to go through the following steps: Create FileSystemObject object, apply related methods, and access object-related properties.
(I) Create FileSystemObject object
The code to create a FileSystemObject object is only 1 line:
var fso = new ActiveXObject("");
After the above code is executed, fso becomes an instance of the FileSystemObject object.
(II) Application of relevant methods
After creating an object instance, you can use the relevant methods of the object. For example, use the CreateTextFile method to create a text file:
var fso = new ActiveXObject("");
var f1 = ("c:\\",true");
(III) Access object-related attributes
To access the relevant properties of an object, you must first establish a handle to the object. This must be achieved through the get series of methods: GetDrive is responsible for obtaining drive information, GetFolder is responsible for obtaining folder information, and GetFile is responsible for obtaining file information. For example, after pointing to the following code, f1 becomes the handle to the file c:\:
var fso = new ActiveXObject("");
var f1 = ("c:\\");
Then, use f1 to access the object's related properties. for example:
var fso = new ActiveXObject("");
var f1 = ("c:\\");
alert("File last modified: " + );
After executing the last sentence above, the last modified date attribute value of c:\ will be displayed.
But one thing is to note: for objects created using the create method, there is no need to use the get method to get the object handle. At this time, just use the handle name created by the create method to directly:
var fso = new ActiveXObject("");
var f1 = ("c:\\",true");
alert("File last modified: " + );
3. Operate drives (Drives)
It is easy to programmatically operate drives and folders using FileSystemObject objects, just like interacting with files in a Windows file browser, such as copying, moving folders, and obtaining folder properties.
(I) Drives object properties
The Drive object is responsible for collecting physical or logical drive resource content in the system. It has the following properties:
l TotalSize: The drive size calculated in bytes (bytes).
l AvailableSpace or FreeSpace: The free space of the drive calculated in bytes.
l DriveLetter: drive letters.
l DriveType: Drive type, the values are: removable (movable media), fixed (fixed media), network (network resources), CD-ROM or RAM disk.
l SerialNumber: The series code of the drive.
l FileSystem: The file system type of the drive, the values are FAT, FAT32 and NTFS.
l IsReady: Whether the drive is available.
l ShareName: ShareName.
l VolumeName: volume name.
l Path and RootFolder: the path or root directory name of the drive.
(II) Drive object operation routine
The following routine displays information such as the volume label, total capacity and available space of drive C:
var fso, drv, s ="";
fso = new ActiveXObject("");
drv = (("c:\\"));
s += "Drive C:" + " - ";
s += + "\n";
s += "Total Space: " + / 1024;
s += " Kb" + "\n";
s += "Free Space: " + / 1024;
s += " Kb" + "\n";
alert(s);
4. Operation folders (Folders)
Operations involving folders include creating, moving, deleting, and obtaining related attributes.
Folder object operation routine:
The following routine will practice getting the parent folder name, creating a folder, deleting a folder, and determining whether it is a root directory:
var fso, fldr, s = "";
// Create a FileSystemObject object instance
fso = new ActiveXObject("");
// Get the Drive object
fldr = ("c:\\");
// Show the parent directory name
alert("Parent folder name is: " + fldr + "\n");
// Show the name of the drive
alert("Contained on drive " + + "\n");
// Determine whether it is the root directory
if ()
alert("This is the root folder.");
else
alert("This folder isn't a root folder.");
alert("\n\n");
// Create a new folder
("C:\\Bogus");
alert("Created folder C:\\Bogus" + "\n");
// Show the basic name of the folder, not including the path name
alert("Basename = " + ("c:\\bogus") + "\n");
// Delete the created folder
("C:\\Bogus");
alert("Deleted folder C:\\Bogus" + "\n");
5. Operation files (Files)
The operations on files are more complicated than the drive (Drive) and folder (Folder) operations mentioned above. They are basically divided into the following two categories: creation, copy, move, delete operations, and creation, addition, delete and read operations of file content. The following are detailed introductions.
(I) Create a file
There are 3 methods to create an empty text file, which is sometimes called a text stream.
The first is to use the CreateTextFile method. The code is as follows:
var fso, f1;
fso = new ActiveXObject("");
f1 = ("c:\\", true);
The second is to use the OpenTextFile method and add the ForWriting property, the value of ForWriting is 2. The code is as follows:
var fso, ts;
var ForWriting= 2;
fso = new ActiveXObject("");
ts = ("c:\\", ForWriting, true);
The third method is to use the OpenAsTextStream method, and the ForWriting property must also be set. The code is as follows:
var fso, f1, ts;
var ForWriting = 2;
fso = new ActiveXObject("");
("c:\\");
f1 = ("c:\\");
ts = (ForWriting, true);
(II) Add data to the file
When a file is created, you generally need to follow the steps of "Open file -> Fill in data -> Close file" to achieve the purpose of adding data to the file.
To open a file, you can use the OpenTextFile method of the FileSystemObject object, or use the OpenAsTextStream method of the File object.
To fill in the data, use the Write, WriteLine or WriteBlankLines method of the TextStream object. In the same way, the function of writing data is that the Write method does not add a new line break at the end of the write data, the WriteLine method needs to add a new line break at the end, and WriteBlankLines adds one or more blank lines.
Close the file using the Close method of the TextStream object.
(III) Create files and add data routines
The following code combines the steps of creating a file, adding data, and closing a file to apply:
var fso, tf;
fso = new ActiveXObject("");
// Create a new file
tf = ("c:\\", true);
// Fill in the data and add line breaks
("Testing 1, 2, 3.") ;
// Add 3 blank lines
(3) ;
// Fill in one line without line breaks
("This is a test.");
// Close the file
();
(IV) Read the file content
Reading data from a text file requires the Read, ReadLine, or ReadAll method of the TextStream object. The Read method is used to read a specified number of characters in a file; the ReadLine method reads a whole line, but does not include line breaks; the ReadAll method reads the entire content of the text file. The read content is stored in string variables for display and analysis. When reading file contents using Read or ReadLine methods, if you want to skip some parts, you need to use the Skip or SkipLine methods.
The following code demonstrates opening the file, filling in the data, and then reading the data:
var fso, f1, ts, s;
var ForReading = 1;
fso = new ActiveXObject("");
// Create a file
f1 = ("c:\\", true);
// Fill in a row of data
("Hello World");
(1);
// Close the file
();
// Open the file
ts = ("c:\\", ForReading);
// Read a line of content of the file to a string
s = ();
// Display string information
alert("File contents = '" + s + "'");
// Close the file
();
(V) Move, copy and delete files
For the above three file operations, JavaScript has two corresponding methods: either for moving files; or for copying files; or for deleting files.
The following code demonstrates creating a text file in the root directory of drive C, filling in some contents, then moving the file to the \tmp directory, then creating a file copy under the directory \temp, and finally deleting the files in these two directories:
var fso, f1, f2, s;
fso = new ActiveXObject("");
f1 = ("c:\\", true);
// Write a line
("This is a test.");
// Close the file
();
// Get the file handle in C:\root directory
f2 = ("c:\\");
// Move the file to the \tmp directory
("c:\\tmp\\");
// Copy the file to the \temp directory
("c:\\temp\\");
// Get the file handle
f2 = ("c:\\tmp\\");
f3 = ("c:\\temp\\");
// Delete the file
();
();
6. Conclusion
Through the above introduction and examples of various objects, properties and methods of FileSystemObject, I believe you have a clear understanding of how to use the javascript language to operate drives, files and folders on pages. However, the routines mentioned above are very simple. To fully and flexibly master the JavaScript file operation technology, a lot of practical practice is required. And there is also a reminder that since it involves advanced operations such as reading and writing files in the browser, for the default browser security level, there will be a message prompt before the code is run. Please remind visitors to pay attention in the actual environment.
1. Function implementation core: FileSystemObject object
To implement file operation functions in javascript, we mainly rely on the FileSystemobject object.
2. FileSystemObject Programming
Programming using FileSystemObject object is very simple. Generally, you have to go through the following steps: Create FileSystemObject object, apply related methods, and access object-related properties.
(I) Create FileSystemObject object
The code to create a FileSystemObject object is only 1 line:
var fso = new ActiveXObject("");
After the above code is executed, fso becomes an instance of the FileSystemObject object.
(II) Application of relevant methods
After creating an object instance, you can use the relevant methods of the object. For example, use the CreateTextFile method to create a text file:
var fso = new ActiveXObject("");
var f1 = ("c:\\",true");
(III) Access object-related attributes
To access the relevant properties of an object, you must first establish a handle to the object. This must be achieved through the get series of methods: GetDrive is responsible for obtaining drive information, GetFolder is responsible for obtaining folder information, and GetFile is responsible for obtaining file information. For example, after pointing to the following code, f1 becomes the handle to the file c:\:
var fso = new ActiveXObject("");
var f1 = ("c:\\");
Then, use f1 to access the object's related properties. for example:
var fso = new ActiveXObject("");
var f1 = ("c:\\");
alert("File last modified: " + );
After executing the last sentence above, the last modified date attribute value of c:\ will be displayed.
But one thing is to note: for objects created using the create method, there is no need to use the get method to get the object handle. At this time, just use the handle name created by the create method to directly:
var fso = new ActiveXObject("");
var f1 = ("c:\\",true");
alert("File last modified: " + );
3. Operate drives (Drives)
It is easy to programmatically operate drives and folders using FileSystemObject objects, just like interacting with files in a Windows file browser, such as copying, moving folders, and obtaining folder properties.
(I) Drives object properties
The Drive object is responsible for collecting physical or logical drive resource content in the system. It has the following properties:
l TotalSize: The drive size calculated in bytes (bytes).
l AvailableSpace or FreeSpace: The free space of the drive calculated in bytes.
l DriveLetter: drive letters.
l DriveType: Drive type, the values are: removable (movable media), fixed (fixed media), network (network resources), CD-ROM or RAM disk.
l SerialNumber: The series code of the drive.
l FileSystem: The file system type of the drive, the values are FAT, FAT32 and NTFS.
l IsReady: Whether the drive is available.
l ShareName: ShareName.
l VolumeName: volume name.
l Path and RootFolder: the path or root directory name of the drive.
(II) Drive object operation routine
The following routine displays information such as the volume label, total capacity and available space of drive C:
var fso, drv, s ="";
fso = new ActiveXObject("");
drv = (("c:\\"));
s += "Drive C:" + " - ";
s += + "\n";
s += "Total Space: " + / 1024;
s += " Kb" + "\n";
s += "Free Space: " + / 1024;
s += " Kb" + "\n";
alert(s);
4. Operation folders (Folders)
Operations involving folders include creating, moving, deleting, and obtaining related attributes.
Folder object operation routine:
The following routine will practice getting the parent folder name, creating a folder, deleting a folder, and determining whether it is a root directory:
var fso, fldr, s = "";
// Create a FileSystemObject object instance
fso = new ActiveXObject("");
// Get the Drive object
fldr = ("c:\\");
// Show the parent directory name
alert("Parent folder name is: " + fldr + "\n");
// Show the name of the drive
alert("Contained on drive " + + "\n");
// Determine whether it is the root directory
if ()
alert("This is the root folder.");
else
alert("This folder isn't a root folder.");
alert("\n\n");
// Create a new folder
("C:\\Bogus");
alert("Created folder C:\\Bogus" + "\n");
// Show the basic name of the folder, not including the path name
alert("Basename = " + ("c:\\bogus") + "\n");
// Delete the created folder
("C:\\Bogus");
alert("Deleted folder C:\\Bogus" + "\n");
5. Operation files (Files)
The operations on files are more complicated than the drive (Drive) and folder (Folder) operations mentioned above. They are basically divided into the following two categories: creation, copy, move, delete operations, and creation, addition, delete and read operations of file content. The following are detailed introductions.
(I) Create a file
There are 3 methods to create an empty text file, which is sometimes called a text stream.
The first is to use the CreateTextFile method. The code is as follows:
var fso, f1;
fso = new ActiveXObject("");
f1 = ("c:\\", true);
The second is to use the OpenTextFile method and add the ForWriting property, the value of ForWriting is 2. The code is as follows:
var fso, ts;
var ForWriting= 2;
fso = new ActiveXObject("");
ts = ("c:\\", ForWriting, true);
The third method is to use the OpenAsTextStream method, and the ForWriting property must also be set. The code is as follows:
var fso, f1, ts;
var ForWriting = 2;
fso = new ActiveXObject("");
("c:\\");
f1 = ("c:\\");
ts = (ForWriting, true);
(II) Add data to the file
When a file is created, you generally need to follow the steps of "Open file -> Fill in data -> Close file" to achieve the purpose of adding data to the file.
To open a file, you can use the OpenTextFile method of the FileSystemObject object, or use the OpenAsTextStream method of the File object.
To fill in the data, use the Write, WriteLine or WriteBlankLines method of the TextStream object. In the same way, the function of writing data is that the Write method does not add a new line break at the end of the write data, the WriteLine method needs to add a new line break at the end, and WriteBlankLines adds one or more blank lines.
Close the file using the Close method of the TextStream object.
(III) Create files and add data routines
The following code combines the steps of creating a file, adding data, and closing a file to apply:
var fso, tf;
fso = new ActiveXObject("");
// Create a new file
tf = ("c:\\", true);
// Fill in the data and add line breaks
("Testing 1, 2, 3.") ;
// Add 3 blank lines
(3) ;
// Fill in one line without line breaks
("This is a test.");
// Close the file
();
(IV) Read the file content
Reading data from a text file requires the Read, ReadLine, or ReadAll method of the TextStream object. The Read method is used to read a specified number of characters in a file; the ReadLine method reads a whole line, but does not include line breaks; the ReadAll method reads the entire content of the text file. The read content is stored in string variables for display and analysis. When reading file contents using Read or ReadLine methods, if you want to skip some parts, you need to use the Skip or SkipLine methods.
The following code demonstrates opening the file, filling in the data, and then reading the data:
var fso, f1, ts, s;
var ForReading = 1;
fso = new ActiveXObject("");
// Create a file
f1 = ("c:\\", true);
// Fill in a row of data
("Hello World");
(1);
// Close the file
();
// Open the file
ts = ("c:\\", ForReading);
// Read a line of content of the file to a string
s = ();
// Display string information
alert("File contents = '" + s + "'");
// Close the file
();
(V) Move, copy and delete files
For the above three file operations, JavaScript has two corresponding methods: either for moving files; or for copying files; or for deleting files.
The following code demonstrates creating a text file in the root directory of drive C, filling in some contents, then moving the file to the \tmp directory, then creating a file copy under the directory \temp, and finally deleting the files in these two directories:
var fso, f1, f2, s;
fso = new ActiveXObject("");
f1 = ("c:\\", true);
// Write a line
("This is a test.");
// Close the file
();
// Get the file handle in C:\root directory
f2 = ("c:\\");
// Move the file to the \tmp directory
("c:\\tmp\\");
// Copy the file to the \temp directory
("c:\\temp\\");
// Get the file handle
f2 = ("c:\\tmp\\");
f3 = ("c:\\temp\\");
// Delete the file
();
();
6. Conclusion
Through the above introduction and examples of various objects, properties and methods of FileSystemObject, I believe you have a clear understanding of how to use the javascript language to operate drives, files and folders on pages. However, the routines mentioned above are very simple. To fully and flexibly master the JavaScript file operation technology, a lot of practical practice is required. And there is also a reminder that since it involves advanced operations such as reading and writing files in the browser, for the default browser security level, there will be a message prompt before the code is run. Please remind visitors to pay attention in the actual environment.