Invert letter case

martoufmarty · June 7th, 2008, 05:38 PM

Hi, I'm trying to invert the cases of a string using charCodeAt to determine if it's already uppercase or lowercase so I would be able to convert it.

This is what I have going on, but it's not exactly working.

<html>

<head>
<title>charCodeAt() - Ex. 3</title>

<script language="javascript" type="text/javascript">

var textodoom;

textodoom = new String("This is Josephine's string");

var textodoom_array = textodoom.split(" ");

var charCheck;

function inverttext() {

    for (i=0; i<textodoom_array.length; i++) {

        charCheck = textodoom_array.charCodeAt(i);

        if ((charCheck > 64) && (charCheck < 91)) {

            var lowerInvert = (textodoom_array(i)).toLowerCase();

        }

        if ((charCheck > 64) && (charCheck < 91)) {

            var upperInvert = (textodoom_array(i)).toUpperCase();

        }

        if (i >= textdoom_array.length) {

            for (j=0; j<textodoom_array.length; j++) {

                document.write(textodoom_array(j));
            }

        }

    }

}

</script>

</head>

<body>

<form name="buttonForm">

<p id="fancytext">This is Josephine's string</p>

<input type="button" name="imabutton" onClick="inverttext();" value="Click to invert string." />

<p id="othertext"> </p>

</form>

</body>

</html>

Can someone tell me what I'm doing wrong?

martoufmarty · June 7th, 2008, 08:44 PM

I've gotten a little bit ahead.

<html>

<head>
<title>charCodeAt() - Ex. 3</title>

<script language="javascript" type="text/javascript">

var textodoom;

textodoom = "This is Josephine's string";

var charCheck;

var upperInvert = 0;

var lowerInvert = 0;

var letArray = new Array();

var otArray = new Array();

function inverttext() {

    for (i=0; i<=(textodoom.length-1); i++) {

        charCheck = textodoom.charCodeAt(i);

        if ((charCheck > 64) && (charCheck < 91)) {

            lowerInvert = (textodoom[i]).toLowerCase();

      var lowerRep = (textodoom[i]).replace((textodoom.charAt(i)),lowerInvert);

        }

        if ((charCheck > 96) && (charCheck < 123)) {

            upperInvert = (textodoom[i]).toUpperCase();

      var upperRep = (textodoom[i]).replace((textodoom.charAt(i)),upperInvert);

        }

    document.write(lowerRep + upperRep);

   }

}

</script>

</head>

<body>

<form name="buttonForm">

<p id="fancytext">This is Josephine's string</p>

<input type="button" name="imabutton" onClick="inverttext();" value="Click to invert string." />

<p id="othertext"> </p>

</form>

</body>

</html>

When I run the function, it gives me:

tundefinedtHtItStStItStSjSjOjSjEjPjHjIjNjEjEjSjSjS jTjRjIjNjG

How would I be able to stop it from doing that and actually displaying the sentence?

vinod_yadav1919 · June 8th, 2008, 01:07 PM

Hii martoufmarty!!

Hope this will help you

<script>

function my()
{

textodoom = "This is Josephine's string";
str="";
for (i=0; i<textodoom.length; i++)
{
currStr=textodoom.charAt(i)
mystr=(currStr==currStr.toUpperCase())?currStr.toL owerCase():currStr.toUpperCase();
str=str+""+mystr
}
alert("final=="+str)
}

</script>

<body>

<p id="fancytext">This is Josephine's string</p>

<input type="button" name="imabutton" onclick="my();" value="Click to invert string." >

Cheers :)

vinod

Old Pedant · June 8th, 2008, 06:59 PM

You can do that somewhat more compactly...

function my(inString)
{
    var outString = "";
    for( var i=0; i < inString.length; ++i )
    {
        var ch = inString.charAt(i);
        outString += ( ch >= 'A' && ch <= 'Z' ) ? ch.toLowerCase() : ch.toUpperCase();
    }
    return outString;
}

martoufmarty · June 8th, 2008, 08:45 PM

Thanks for all your help, guys. I figured out what I was doing. Got it working. Yay! :D