Special character validation using JavaScript

Question

Special characters <, >, %, '', "", $ and ^ are not allowed in a textbox. I need to put a validation check to restrict these characters on submit along with the null check.

I wrote entire validation code in a function and calling it on click of the submit button, but the function is not recognised on click.

Please help me write some JavaScript code to achieve this functionality.

You might want to post your function here. How else would people be able to tell what's wrong with it? — Tomalak, May 08 '09 at 12:21
@Tomalak: it sounds like the function isn't the problem. It's calling it and cancelling the submit based on the results that he needs help with. The function itself could do anything. — Joel Coehoorn, May 08 '09 at 13:04
http://stackoverflow.com/questions/756567/regular-expression-for-excluding-special-characters/756612 — input, May 08 '09 at 12:09

score 7 · Answer 1 · edited Nov 15 '11 at 05:03

7

A much simpler way is to use indexOf in javascript,

function isSpclChar(){
   var iChars = "!@#$%^&*()+=-[]\\\';,./{}|\":<>?";
   if(document.qfrm.q.value.indexOf(iChars) != -1) {
     alert ("The box has special characters. \nThese are not allowed.\n");
     return false;
   }
}

edited Nov 15 '11 at 05:03

Sam Saffron

128,308
78
326
506

answered Sep 21 '10 at 18:24

Hitesh Agarwal

201
3
4

score 2 · Answer 2 · edited Feb 18 '11 at 10:22

2

function isSpclChar(){
var iChars = "!@#$%^&*()+=-[]\\\';,./{}|\":<>?";
for (var i = 0; i < document.qfrm.q.value.length; i++) {
    if (iChars.indexOf(document.qfrm.q.value.charAt(i)) != -1) {
    alert ("The box has special characters. \nThese are not allowed.\n");
    return false;
        }
    }
}

edited Feb 18 '11 at 10:22

Community

1
1

answered Nov 16 '09 at 09:14

Teckie

21
2

score 2 · Answer 3 · edited Oct 08 '18 at 10:29

Try this:

$('#text').keypress(function (e) {
    validationForSpecialchar(e);           
});

function validationForSpecialchar(e){
    var regex = new RegExp("^[a-zA-Z0-9-]+$"); 
    var str = String.fromCharCode(!e.charCode ? e.which : e.charCode);
    if (regex.test(str)) {
        return true;
    }
    e.preventDefault();
    return false;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
Enter something here : <input id="text">

score 0 · Answer 4 · edited Feb 07 '13 at 06:52

function alphanumeric_only(event)
 {
    var keycode;

   keycode=event.keyCode?event.keyCode:event.which;


   if ((keycode == 32) || (keycode >= 47 && keycode <= 57) || (keycode >= 65 && keycode <= 90) || (keycode >= 97 && keycode <= 122)) {

        return true;

    }

    else {
        alert("Sorry You can not insert Special Character");
        return false;

    }
    return true;

}

score 0 · Answer 5 · answered May 08 '09 at 12:08

0

Try something like

<form ... onsubmit="function()">

In function you can get text from your textarea or what you are using. If data is valid function () should return true. Otherwise form wouldn't be submitted.

answered May 08 '09 at 12:08

Roman

64,384
92
238
332

Special character validation using JavaScript

5 Answers5

Linked