How to use radio on change event?

You can use this which refers to the current input element.

$('input[type=radio][name=bedStatus]').change(function() {    if (this.value == 'allot') {        alert("Allot Thai Gayo Bhai");    }    else if (this.value == 'transfer') {        alert("Transfer Thai Gayo");    }});

http://jsfiddle.net/4gZAT/

Note that you are comparing the value against allot in both if statements and :radio selector is deprecated.

In case that you are not using jQuery, you can use the document.querySelectorAll and HTMLElement.addEventListener methods:

var radios = document.querySelectorAll('input[type=radio][name="bedStatus"]');function changeHandler(event) {   if ( this.value === 'allot' ) {     console.log('value', 'allot');   } else if ( this.value === 'transfer' ) {      console.log('value', 'transfer');   }  }Array.prototype.forEach.call(radios, function(radio) {   radio.addEventListener('change', changeHandler);});

An adaptation of the above answer...

$('input[type=radio][name=bedStatus]').on('change', function() {  switch ($(this).val()) {    case 'allot':      alert("Allot Thai Gayo Bhai");      break;    case 'transfer':      alert("Transfer Thai Gayo");      break;  }});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script><input type="radio" name="bedStatus" id="allot" checked="checked" value="allot">Allot<input type="radio" name="bedStatus" id="transfer" value="transfer">Transfer