Integer thousands separator in add node form
you can quickly and easily build a custom module around this:

&lt;form&gt;
    &lt;input type='text' id="input"&gt;
&lt;/form&gt;

&lt;script&gt;
    jQuery('#input').keyup(function (event)
    {
        var value = jQuery('#input').val();

        if(event.which &gt;= 37 &amp;&amp; event.which &lt;= 40)
        {
            event.preventDefault();
        }

        var newvalue = value.replace(/,/g, '');   
        var valuewithcomma = Number(newvalue).toLocaleString('en');   
        jQuery('#input').val(valuewithcomma); 
    });
&lt;/script&gt;


adapted from here

EDIT

This code has been modified and works in Bartik theme, using an Article content type with an integer field 'number' - it simply resets the value of the input and strips the commas before the form is submitted to the server:

&lt;script&gt;
    jQuery('.page-node-add-article .field-name-field-number input').keyup(function (event)
    {
        var value = jQuery('.page-node-add-article .field-name-field-number input').val();

        if(event.which &gt;= 37 &amp;&amp; event.which &lt;= 40)
        {
            event.preventDefault();
        }

        var newvalue = value.replace(/,/g, '');   
        var valuewithcomma = Number(newvalue).toLocaleString('en');   
        jQuery('.page-node-add-article .field-name-field-number input').val(valuewithcomma); 
    });

    jQuery('.node-article-form').submit(function()
    {
        var text = jQuery('.page-node-add-article .field-name-field-number input').val();
        var newtext = "";
        for (var i = 0; i &lt; text.length; i++)
        {
            var c = text.charAt(i);
            if (c != ',')
            {
                newtext += c;
            }
        }
        jQuery('.page-node-add-article .field-name-field-number input').val(newtext);
    });
&lt;/script&gt;