Read to end of text file

tonyp12 · 01-15-2007, 02:37 AM

This programs works to read a file, but only if I know how many lines of text there are.

How do I tell the loop to stop when end of file?

hint: save this code with .hta extension instead of .html (no warnings)

<html>
<head>
<title></title>
<script>

function Readfile()
{
keys=new Array();
var fso=new ActiveXObject("Scripting.FileSystemObject");
var openkeys=fso.openTextFile("C:\\testfile.txt",1);
var keystring=new Array();

i = 0
while (i <= 10) // this wile stop after 10 read lines, (keystring[i]!= null) does not work
{
keystring[i]=openkeys.readline();
i++
}

for(var i=0;i<10;i++){
document.write(keystring[i] +"<br>")
}

openkeys.close()
}
</script>
</head>
<body>
<a href="#" onClick="Readfile()">Click to read txt file</a>
</body>
</html>

TripperTreats · 01-15-2007, 02:51 AM

I don't know anything about using ActiveXObject, but I'm assuming that if you try to readline() at the end of the document, it will return null or false or something. So can you not do something like this:

Code:

for (var i=0; true; i++) {
  var temp = openkeys.readline();
  if (temp) keystring[i]=temp else break;
}

shyam · 01-15-2007, 02:52 AM

I found this to be a lot simpler

Code:

function Readfile() {
  keys=new Array();
  var fso=new ActiveXObject("Scripting.FileSystemObject");
  var openkeys=fso.openTextFile("C:\\testfile.txt",1);
  var keystring=[];
  var buf = openkeys.readall();
  keystring = buf.split('\n'); // to get all individual lines
  document.write(keystring.join('<br>'));
  openkeys.close()
}

tonyp12 · 01-15-2007, 02:59 AM

shyam, it worked perfect.

shyam · 01-15-2007, 03:00 AM

next time peek around here

tonyp12 · 01-16-2007, 11:01 PM

keys=new Array();

Why is this there?, I can not see that it used.

david_kw · 01-16-2007, 11:32 PM

I imagine he put it there because it was in your code first.

david_kw

tonyp12 · 01-21-2007, 12:06 AM

I also found out how to read unicode, the -1 is for unicode

var openkeys=fso.openTextFile("testtext.txt",1,false,-1);

If I use charCodeAt(0) for a file that starts with hex 41 42 (text for AB)
I get an answer of 16961 = 42 41 (text for BA)
So it kind of pairs them in reverse, so some bit shifting have to be done of if I want to get the bytes.

But if you want to read pure raw data you have to use read(number of bytes/2)
instead of readall()

Example that reads the notepad.exe file in rawdata mode and
shows the hex value of 16 bytes starting on offset 132.
Rename to .hta

Code:

<html>
<head>
<title>Show hex value of data in file</title>

<script>

 function Readfile() {
  
  var fso=new ActiveXObject("Scripting.FileSystemObject");
  var openkeys=fso.openTextFile("C:\\WINDOWS/NOTEPAD.EXE",1,false,-1);
  var buf = openkeys.read(66);     // read first 132 bytes
  var buf = openkeys.read(8);      // read the 16 bytes we want.

  var hD='0123456789ABCDEF';
  for (var i=0; i<8; i++)
  {
  var d= buf.charCodeAt(i) & 255;   // get the fist 8 bits
  if (d<16){document.write('0')};
  var h = hD.substr(d&15,1);
  while (d>15) {
  d>>=4;
  h=hD.substr(d&15,1)+h;
   }  
  document.write(h + ' ');

  var d= buf.charCodeAt(i)>>8;       // get the top 8 bits
  if (d<16){document.write('0')};
  var h = hD.substr(d&15,1);
  while (d>15) {
  d>>=4;
  h=hD.substr(d&15,1)+h;
   }  
  document.write(h + ' ');
  }

  openkeys.close()
}


</script>
</head>
<body onLoad="Readfile()">

</body>
</html>