Create Auto increment number Column in SharePoint List

Using below code we can show auto increment column number in SharePoint list.First download the Sputility.js file and jquery files after that create a SNO column with

'Single line of text ' Type. From Ribbon under Form Web parts select Default New Form and add the below code using Content Editor web part.

<script src="/SiteAssets/jquery-3.1.1.js"></script>
<script src="/SiteAssets/sputility.js"></script><script>


    // Get the current Site
    var siteUrl = '/';

    function retrieveListItems() {

        var clientContext = new SP.ClientContext(siteUrl);
        // Get the liste instance
        var oList = clientContext.get_web().get_lists().getByTitle('Test List');

        var camlQuery = new SP.CamlQuery();

        // Get only the last element
        camlQuery.set_viewXml('<Query><OrderBy><FieldRef Name=\'ID\' Ascending=\'False\' /></OrderBy></Query><RowLimit>1</RowLimit></View>');
        this.collListItem = oList.getItems(camlQuery);

        clientContext.load(collListItem);

        clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));      

    }

    function onQuerySucceeded(sender, args) {

        var listItemInfo = '';

        var listItemEnumerator = collListItem.getEnumerator();

        while (listItemEnumerator.moveNext()) {
            var oListItem = listItemEnumerator.get_current();

            var listItemInfovalue = oListItem.get_item('SNO');


 

            // create the new id
            SPUtility.GetSPField('SNO').SetValue(parseInt(listItemInfovalue) + 1);
        }

        console.log(listItemInfo.toString());
    }

    function onQueryFailed(sender, args) {
        alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
    }



$(document).ready(function(){
    ExecuteOrDelayUntilScriptLoaded(retrieveListItems, "sp.js");
    });</script>