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.

Answer 1

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;

}

Answer 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;
        }
    }
}   

Answer 3

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;
   }
}

Answer 4

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">

Answer 5

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.