[Javascript] Validation

[Rodney Myers]

Here is some code that ensures that input is permitted characters only -
in this case digits and a point :

function dfix(el){
el.value=decimals(el.value);
}

function decimals(str){ return(clean(str,"1234567890.")) }

function clean(str,permitted){
str=""+str;
var nchar,n;var out="";
for(n=0;n<str.length;n++)
 {
 nchar=str.charAt(n);
 out+=permitted.indexOf(nchar)>-1?nchar:"";
 }
return(out);
}

This code does not verify by an alert but gets in and chucks out the
unwanted characters.
Admittedly this is not always what is wanted, but sometimes it is
appropriate.

<input .... onchange="dfix(this)">

We pass the input object with 'this' and so can set its value
el.value=decimals(el.value);

For A-Za-z we could have
<input .... onchange="azfix(this)">

function azfix(el){
el.value=azAZ(el.value);
}

function azAZ(str){
var permitted="abcdefghijklmnopqrstuvwxyz";
permitted+=permitted.toUpperCase();
return(clean(str,permitted)) }

Noting that the above function clean() is re-used.


hth

Rodney


Mark.Benton at egg.com wrote:

> Can someone tell me or provide some sample code of a function to
> validate that a text box entry is apha charcters only.
>
> Thanks in advance.
>

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Rodney Myers
Based in Oxford, England
Technical Director, Shop at ssistant eCommerce Solutions