Remove Last Comma from a string

This will remove the last comma and any whitespace after it:

str = str.replace(/,\s*$/, "");

It uses a regular expression:

• The / mark the beginning and end of the regular expression

• The , matches the comma

• The \s means whitespace characters (space, tab, etc) and the * means 0 or more

• The $ at the end signifies the end of the string

you can remove last comma from a string by using slice() method, find the below example:

var strVal = $.trim($('.txtValue').val());
var lastChar = strVal.slice(-1);
if (lastChar == ',') {
    strVal = strVal.slice(0, -1);
}

Here is an Example

function myFunction() {
	var strVal = $.trim($('.txtValue').text());
	var lastChar = strVal.slice(-1);
	if (lastChar == ',') { // check last character is string
		strVal = strVal.slice(0, -1); // trim last character
		$("#demo").text(strVal);
	}
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>


<p class="txtValue">Striing with Commma,</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

function removeLastComma(str) {
   return str.replace(/,(\s+)?$/, '');   
}