Invalid Character Entered Error Works in MSIE but not Netscape

The following script shows the user an alert message if he enters a dash (-) in the input field. This works nicely in MSIE, but not in Netscape. Can someone make this work in both browsers? Actually, the alert box appears in netscape nicely, but the resulting page appears. I should not be take to the next page unless I have entered a lowercase letter(s) or UPPERCASE letter(s):

<script>
function validate(field) {
//var valid = "abcdefghijklmnopqrstuvwxyz0123456789"
var valid = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ "
var ok = "yes";
var temp;
for (var i=0; i<field.value.length; i++) {
temp = "" + field.value.substring(i, i+1);
if (valid.indexOf(temp) == "-1") ok = "no";
}
if (ok == "no") {
alert("Name is invalid (numbers and special characters are not allowed)");
field.focus();
field.select();
   }
}
</script>

<input type="text" name="namex" onBlur="validate(this)"
lserranoAsked:
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Lord_McFlyConnect With a Mentor Commented:
I'm not sure what you mean when you say 'but the resulting page appears' - I can see how once your script has performed the validation it can possibly move onto another page.

I offer a slightly different script which will not allow unwanted characters whcih means when the page does move on the field won't contain invalid characters.

function ValidateKeyStroke(Input)
      {
            var control="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
            var newInput="";

            for(i=0;i<Input.value.length;i++)
                  {
                        chck=Input.value.charAt(i);
                        
                        if(control.indexOf(chck,0)!=-1)
                              {
                                    newInput+=chck;
                              }
                  }
            
            Input.value = newInput;
      }


<input type="text" onKeyUp="ValidateKeyStroke(this)">
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lserranoAuthor Commented:
Lord_McFly, I wonder if you can expand of this so that if the user enters an unrealistic name which does not contain any vowels (i.e., a,e,i,o, OR u) such as dffdffsdsfdfs, then the script will erase what he has entered and do not pass the form until he has entered a word which contains at least 1 vowel.
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Lord_McFlyCommented:
Ok I couldn't do it in the same function so I've done the validation when the form is submitted. If the text lacks any vowels it will display an alert but won't allow the page to submit.

<html>
<head>
<title>Example</title>
<script language="JavaScript">
<!--
function ValidateKeyStroke(Input)
      {
            var control="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
            var newInput="";

            for(i=0;i<Input.value.length;i++)
                  {
                        chck=Input.value.charAt(i);
                        
                        if(control.indexOf(chck,0)!=-1)
                              {
                                    newInput+=chck;
                              }
                  }
            
            Input.value = newInput;
      }

function CheckForm(Form)
      {
            
            var control="aeiouAEIOU"
            var chck
            var i
            var ok = false
            
            for(i=0; i<Form.Name.value.length; i++)
                  {
                        chck=Form.Name.value.charAt(i);

                        if(control.indexOf(chck,0)!=-1)
                              {
                                    ok = true
                              }
                  }
            
            if(ok==false)
                  {
                        alert("Name seems invalid")
                  }
                  
            return ok
      }

//-->
</script>
</head>
<body>
<form name="Data" method="post" action="../ASP/UsingDATEDIFF.asp" onSubmit="return CheckForm(this)">
      <input type="text" name="Name" onKeyUp="ValidateKeyStroke(this)" value="">
</form>
</body>
</html>
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lserranoAuthor Commented:
Hmm... your code seems to work awesome as standalone, but when I add it to my existing page (http://www.worldwidelists.com/cgi-bin/lists.cgi?popup.test) and submit, I do not get the alert box. Any ideas why?

By the way, thank you so much for all your help!

L
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Lord_McFlyCommented:
I had a look at the page - I noticed the name of the textbox is 'namex' - this means that the name in the function 'CheckForm(Form)' needs to be changed...

for(i=0; i<Form.namex.value.length; i++)      <------ notice change.
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lserranoAuthor Commented:
Super! Thanks for all your help Lord_McFly! ;-)
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