javascript - Disable symbols and non-letters in input field - Stack Overflow

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I would like to disable all symbols entry into an input field that are not associated with following: letters or numbers or spaces or ampersand symbol or full stop.

E.g. ALLOWED: A-Z, a-z, 0-9, &, ., and space is allowed.

NOT ALLOWED: Every other character e.g. ! @ # $ % ^ * ( ) - + = [ ] ; : ' " < > , / ? | = ` ~ etc.

<input id="ItemName" type="text" />

I would like to disable all symbols entry into an input field that are not associated with following: letters or numbers or spaces or ampersand symbol or full stop.

E.g. ALLOWED: A-Z, a-z, 0-9, &, ., and space is allowed.

NOT ALLOWED: Every other character e.g. ! @ # $ % ^ * ( ) - + = [ ] ; : ' " < > , / ? | = ` ~ etc.

<input id="ItemName" type="text" />

• javascript
• forms
• input
• field

Share Improve this question Follow edited Sep 3, 2015 at 0:33 royhowie 11.2k1414 gold badges5353 silver badges6767 bronze badges asked Sep 3, 2015 at 0:32 Kim TranKim Tran 27911 gold badge44 silver badges1212 bronze badges 2

• What have you tried so far? – nnnnnn Commented Sep 3, 2015 at 0:35
• 1 is HTML5 OK? If so you can use a pattern attribute and give a simple regex. Something like pattern="[A-Za-z0-9& .]*" – dmeglio Commented Sep 3, 2015 at 0:36

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 1

You can register a keypress event handler and return false if you don't "like" the new input :

$('#ItemName').keypress(function (e) {
    var txt = String.fromCharCode(e.which);
    if (!txt.match(/[A-Za-z0-9&. ]/)) {
        return false;
    }
});

JSFiddle: http://jsfiddle/cgx1yqyf/

Note that this solution requires JQuery

The right way is using an "input" event. document.addEventListener('input', script); https://developer.mozilla/en-US/docs/Web/Events/input

Question is old, but it's never too late to answer

$(document).ready(function() {
  //prevent paste
  var usern_paste = document.getElementById('yourid');
  usern_paste.onpaste = e => e.preventDefault();

  //prevent copy
  var usern_drop = document.getElementById('yourid');
  usern_drop.ondrop = e => e.preventDefault();

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

Yes, yes, I know. This question is old. But I'd just give it a try (without jQuery)

HTML

<input type="text" placeholder="Try to put a non-alphabetical character here! (you can put a number and a space too)" id="nochars" />

JS

const input = document.getElementById("nochars"); // gets the element (the input) by it's id
input.addEventListener("input", (event) =>  {
  const char = String.fromCharCode(event.keyCode)); // changes the keycode from a int to a string
  if (!(/[a-zA-Z0-9\s\.$]/.test(char))) {
    event.preventDefault(); // prevents the default (which is adding the character to the value)
  }
});

Also, check on what EventTarget.addEventListener does. (\s is a whitespace - a space)

I would like to disable all symbols entry into an input field that are not associated with following: letters or numbers or spaces or ampersand symbol or full stop.

E.g. ALLOWED: A-Z, a-z, 0-9, &, ., and space is allowed.

NOT ALLOWED: Every other character e.g. ! @ # $ % ^ * ( ) - + = [ ] ; : ' " < > , / ? | = ` ~ etc.

<input id="ItemName" type="text" />

I would like to disable all symbols entry into an input field that are not associated with following: letters or numbers or spaces or ampersand symbol or full stop.

E.g. ALLOWED: A-Z, a-z, 0-9, &, ., and space is allowed.

NOT ALLOWED: Every other character e.g. ! @ # $ % ^ * ( ) - + = [ ] ; : ' " < > , / ? | = ` ~ etc.

<input id="ItemName" type="text" />

• javascript
• forms
• input
• field

Share Improve this question Follow edited Sep 3, 2015 at 0:33 royhowie 11.2k1414 gold badges5353 silver badges6767 bronze badges asked Sep 3, 2015 at 0:32 Kim TranKim Tran 27911 gold badge44 silver badges1212 bronze badges 2

• What have you tried so far? – nnnnnn Commented Sep 3, 2015 at 0:35
• 1 is HTML5 OK? If so you can use a pattern attribute and give a simple regex. Something like pattern="[A-Za-z0-9& .]*" – dmeglio Commented Sep 3, 2015 at 0:36

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 1

You can register a keypress event handler and return false if you don't "like" the new input :

$('#ItemName').keypress(function (e) {
    var txt = String.fromCharCode(e.which);
    if (!txt.match(/[A-Za-z0-9&. ]/)) {
        return false;
    }
});

JSFiddle: http://jsfiddle/cgx1yqyf/

Note that this solution requires JQuery

The right way is using an "input" event. document.addEventListener('input', script); https://developer.mozilla/en-US/docs/Web/Events/input

Question is old, but it's never too late to answer

$(document).ready(function() {
  //prevent paste
  var usern_paste = document.getElementById('yourid');
  usern_paste.onpaste = e => e.preventDefault();

  //prevent copy
  var usern_drop = document.getElementById('yourid');
  usern_drop.ondrop = e => e.preventDefault();

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

Yes, yes, I know. This question is old. But I'd just give it a try (without jQuery)

HTML

<input type="text" placeholder="Try to put a non-alphabetical character here! (you can put a number and a space too)" id="nochars" />

JS

const input = document.getElementById("nochars"); // gets the element (the input) by it's id
input.addEventListener("input", (event) =>  {
  const char = String.fromCharCode(event.keyCode)); // changes the keycode from a int to a string
  if (!(/[a-zA-Z0-9\s\.$]/.test(char))) {
    event.preventDefault(); // prevents the default (which is adding the character to the value)
  }
});

Also, check on what EventTarget.addEventListener does. (\s is a whitespace - a space)

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