Carriage return inefficiency in a textarea control

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  • Patrick
    #1

    Carriage return inefficiency in a textarea control

    I'm developing an application which requires
    a textarea to display large amounts of data.
    I'm storing the information in an array and then
    using join to dump the contents into the textarea.
    It appears, however that textareas don't handle
    carriage returns very well as illustrated by the following code.
    If would appreciate if anyone knows the reason for this behavior
    and a possible workaround.

    <HTML><HEAD>
    <TITLE>Textarea </TITLE>
    <SCRIPT>
    var arr= new Array;
    function GenString(s){
    arr.length=0;
    for (var i=0;i<5000;i++)
    arr[arr.length] = i + ' = [abcdefghijklmno pqrstuvwxyz]'
    var d = new Date();
    if (s=='||')form1. textarea1.value =arr.join('||')
    else form1.textarea1 .value=unescape (arr.join('\n') )
    var d1= new Date()
    alert((d1-d)/1000 + ' seconds' + '\n' + 'Textarea length= ' +
    form1.textarea1 .value.length);
    }
    </SCRIPT>
    </HEAD>
    <BODY>
    <FORM NAME="form1">
    <TEXTAREA ROWS="10" COLS="40" NAME="textarea1 "></TEXTAREA>
    <BR><INPUT TYPE="button" VALUE="Generate || string" NAME="button1"
    ONCLICK="GenStr ing('||')">
    <INPUT TYPE="button" VALUE="Generate \n string" NAME="button1"
    ONCLICK="GenStr ing('\n')">
    </FORM>
    </BODY>
    </HTML>
    Tags: None
    • Lasse Reichstein Nielsen
      #2
      Re: Carriage return inefficiency in a textarea control

      patd@ceposystem s.com.au (Patrick) writes:
      [color=blue]
      > It appears, however that textareas don't handle
      > carriage returns very well as illustrated by the following code.
      > If would appreciate if anyone knows the reason for this behavior
      > and a possible workaround.[/color]

      You failed to tell us what the behavior is, what you expected, and
      which browser exhibits the bad behavior.

      Is the problem that the string joined with "\n" takes ~four times longer
      to insert into the textarea?
      In that case, it has nothing to do with Javascript, but is an artifact of
      the underlying implementation of text areas. Any solution would include
      not using a text area.
      /L
      --
      Lasse Reichstein Nielsen - lrn@hotpop.com
      Art D'HTML: <URL:http://www.infimum.dk/HTML/randomArtSplit. html>
      'Faith without judgement merely degrades the spirit divine.'

        Comment

        • Patrick
          #3
          Re: Carriage return inefficiency in a textarea control

          > > It appears, however that textareas don't handle[color=blue][color=green]
          > > carriage returns very well as illustrated by the following code.
          > > If would appreciate if anyone knows the reason for this behavior
          > > and a possible workaround.[/color]
          >
          > You failed to tell us what the behavior is, what you expected, and
          > which browser exhibits the bad behavior.
          >
          > Is the problem that the string joined with "\n" takes ~four times longer
          > to insert into the textarea?
          > In that case, it has nothing to do with Javascript, but is an artifact of
          > the underlying implementation of text areas. Any solution would include
          > not using a text area.
          > /L[/color]

          Lasse

          Thanks for your reply.

          To clarify: I'm experiencing this behavior on IE5.0. (I'm actually
          developing for the Pocket PC version of IE which in this case shows
          the same behavior as IE5.0). When you run the supplied code snippet in
          IE5 - the double pipe "||"
          renders the entire string to the text area in approx. .1 of a second
          as opposed to the "\n" version which takes 7.5 seconds - for the same
          sized string. I've run the code on some other browsers with the
          following results:
          Browser "||" "\n"
          IE5.0 0.12 sec 7.5 sec
          IE6.0 0.15 sec 0.7 sec
          Opera7.11 12 sec 12 sec
          NN7.02 4.5 sec 12 sec

          As you see quite a difference between browsers and in some instances
          the render times for the two strings. What is even more curious is
          that Netscape reports a different string size ie. 178889 for the "\n"
          option as opposed to 183888 for the "||" option. I tend to agree with
          you that this text area behavior seems to be due to the underlying
          browser implementation - if there are any solutions that would prevent
          this behavior - is another question.

            Comment

            • Lasse Reichstein Nielsen
              #4
              Re: Carriage return inefficiency in a textarea control

              patd@ceposystem s.com.au (Patrick) writes:
              [color=blue]
              > When you run the supplied code snippet
              > in IE5 - the double pipe "||" renders the entire string to the text
              > area in approx. .1 of a second as opposed to the "\n" version which
              > takes 7.5 seconds - for the same sized string. I've run the code on
              > some other browsers with the following results:[/color]
              [color=blue]
              > Browser "||" "\n"
              > IE5.0 0.12 sec 7.5 sec
              > IE6.0 0.15 sec 0.7 sec
              > Opera7.11 12 sec 12 sec[/color]

              Opera 7.2 is faster, and gives results similar to IE 6.
              [color=blue]
              > NN7.02 4.5 sec 12 sec
              >
              > As you see quite a difference between browsers and in some instances
              > the render times for the two strings.[/color]

              Yes, quite a difference. Are IE 5 and IE 6 running on different
              operating systems? Because I would expect the operating system to be
              the important factor if the browser uses standard system widgets
              (which I don't think Mozilla/NN7 does).
              [color=blue]
              > What is even more curious is that Netscape reports a different
              > string size ie. 178889 for the "\n" option as opposed to 183888 for
              > the "||" option.[/color]

              That is probably because Mozilla uses UNIX End-of-line encoding (one
              newline, 0x0a) and the other browsers uses DOS/Windows EOL (carrige
              return+newline, 0x0d 0x0a).
              [color=blue]
              > I tend to agree with you that this text area behavior seems to be
              > due to the underlying browser implementation - if there are any
              > solutions that would prevent this behavior - is another question.[/color]

              I doubt it.
              /L
              --
              Lasse Reichstein Nielsen - lrn@hotpop.com
              Art D'HTML: <URL:http://www.infimum.dk/HTML/randomArtSplit. html>
              'Faith without judgement merely degrades the spirit divine.'

                Comment

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