Replace non-alphanumeric characters by underscore.

My goal is to replace all non-alphanumeric characters by '_'.  The following is the code I had.  At the end, when I display the final string, it was empty.  Please help me.  Thanks in advance.

==================================================
var str = "a b.3-4+";     // final string should be "a_b_3_4_"
var choice = "";

for ( i = 0; i < str.length; i++ )
    if ( str.charAt( i ) == ' ' || str.charAt( i ) == '-' ||
            str.charAt( i ) == '+' || str.charAt( i ) == '=' ||
            str.charAt( i ) == '*' || str.charAt( i ) == '&' ||
            str.charAt( i ) == '%' || str.charAt( i ) == '$' ||
            str.charAt( i ) == '@' || str.charAt( i ) == '#' ||
            str.charAt( i ) == ',' || str.charAt( i ) == '.' ||
            str.charAt( i ) == '>' || str.charAt( i ) == '<' )
        choice.concat( "_" );
    else
        choice.concat( str.charAt( i ));

alert( choice );
=========================================

Is there a better way to achieve what I wanted?

Thanks experts.
LVL 1
szetoaAsked:
Who is Participating?
 
ahosangConnect With a Mentor Finance Systems DeveloperCommented:
use regular expressions:
<html>
<head>
     <title>Untitled</title>
<script>
function replaceChars(textField) {
  var nonAlphaNum=/[^0-9,a-z,A-Z]/gi;
  textField.value=textField.value.replace(nonAlphaNum, "_");
}
</script>
</head>

<body>

test<br>
<form>
<input name="text1" type="text" value="">
<input type="button" value="check it" onclick="replaceChars(this.form.text1)">
</form>

</body>
</html>
0
 
daniel_cCommented:
listening...
0
 
a.marshCommented:
First of all here is a much more efficient solution:

<html>
<head>
<script language="javascript">
<!--

function convertName(val, resultObj){
  var test = new RegExp("[^0-9,a-z,A-Z]", "g");

  resultObj.value = val.replace(test, "_");
}

//-->
</script>
</head>
<body>
<form>
<input type="text" name="str1" value="">
<p><input type="button" value="convert..." onClick="convertName(this.form.str1.value, this.form.str2);"></p>
<input type="text" name="str2" value="">
</form>
</body>
</html>

Ant
0
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a.marshCommented:
And here is the working version of your code:

<html>
<head>
<script language="javascript">
<!--

var str = "a b.3-4+";     // final string should be "a_b_3_4_"
var choice = "";

for ( i = 0; i < str.length; i++ )
   if ( str.charAt( i ) == ' ' || str.charAt( i ) == '-' ||
           str.charAt( i ) == '+' || str.charAt( i ) == '=' ||
           str.charAt( i ) == '*' || str.charAt( i ) == '&' ||
           str.charAt( i ) == '%' || str.charAt( i ) == '$' ||
           str.charAt( i ) == '@' || str.charAt( i ) == '#' ||
           str.charAt( i ) == ',' || str.charAt( i ) == '.' ||
           str.charAt( i ) == '>' || str.charAt( i ) == '<' )
       choice += "_";
   else
       choice += str.charAt(i);

alert( choice );

//-->
</script>
</head>
<body>
</body>
</html>
0
 
ahosangFinance Systems DeveloperCommented:
Dang Ant, you're pretty sharp mister :-)
0
 
a.marshCommented:
;o)

Ant
0
 
szetoaAuthor Commented:
Thank you both Ant and ahosang.  The regular expression solution works like a charm.  Since Ant gave me the answer first, I am going to award the points to him.  Thanks again.
0
 
a.marshCommented:
Think you made a bit of a mistake there then szetoa......the button is at the top of the comment that you want to accept......

Be careful in the future.... :o)

I shall get Community Support to resolve this.

:o)

Ant
0
 
szetoaAuthor Commented:
Thank you both Ant and ahosang.  The regular expression solution works like a charm.  Since Ant gave me the answer first, I am going to award the points to him.  Thanks again.
0
 
szetoaAuthor Commented:
Sorry Ant,  I am a little confused about the button. I just posted another question with the same amount of points just for you.
0
 
Computer101Commented:
Points refunded so that they can be used in the question posted by szetoa for A.marsh.

Thank you
Computer101
Community Support Moderator
0
 
a.marshCommented:
Just to try to keep things all tied together, points awarded here:

http://www.experts-exchange.com/jsp/qShow.jsp?qid=20143064

:o)

Ant
0
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