CODEWITHSUNDEEP
javascriptjqueryhtmlforms
Sao Tith
Sao Tith

Reputation: 81

Jquery on keypress

I'm looking for a function that gives an alert when a certain character key (g) is pressed in the first position of a postal code, and then disables the submit button if the postal code has a letter G in the beginning. Is this possible?

My current code to detect a key up on the postal code field at the moment is this:

$(document).ready(function() {
  var someTextInputField = "#postal-code";
  
  $(someTextInputField).on("keyup", function() {
    alert('not a valid postal code');
  });
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input id="postal-code" />

Upvotes: 1

Views: 370

Answers (3)

redbmk
redbmk

Reputation: 4796

Javascript without extra libraries

document.addEventListener("input", function(e) {
  if (e.target.id === "postal-code") {
    var disable = /^g/i.test(e.target.value),
      submit = document.getElementById("submit");
    
    if (disable && !submit.disabled) {
      alert("You cannot start a postal code with a G");
    }
    
    submit.disabled = disable;
  }
});
<input placeholder="Address" />
<input id="postal-code" placeholder="Postal Code" />
<button id="submit">Submit</button>

jQuery

$(document).on("input", "#postal-code", function (e) {
  var disable = /^g/i.test(this.value),
      $submit = $("#submit");
    
    if (disable && !$submit.prop("disabled")) {
      alert("You cannot start a postal code with a G");
    }
    
    $submit.prop("disabled", disable);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input placeholder="Address" />
<input id="postal-code" placeholder="Postal Code" />
<button id="submit">Submit</button>

Upvotes: 1

Barmar
Barmar

Reputation: 782653

You can use this.value[0] to get the first character of the input. Then test whether it's one of the allowed characters.

$("#input").on("keyup", function() {
  if (this.value != '') {
    var firstchar = this.value[0].toUpperCase();
    if (firstchar != 'A' && firstchar != 'G') {
      alert('not a valid postal code');
      $("#submitID").prop("disabled", true);
    } else {
      $("#submitID").prop("disabled", false);
    }
  }
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input id="input"/>

Upvotes: 0

Jonathan Anctil
Jonathan Anctil

Reputation: 1037

Check this fiddle http://jsfiddle.net/oyc2L9sy/12/

html:

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

javascript:

$(document).ready(function() {
    $("#test").on("keypress", function(e) {  
        if ((e.keyCode == '65') ||
            (e.keyCode == '71')) { 
            alert('not a valid postal code');
            return false;
        }
    });  
});

Upvotes: 0

Related Questions