I created a helper a few months back that used DATA URIs to download JSON to CSV, but due to IE’s implementation of DATA URIs (or lack of), it does not work for IE (all versions). Here is the same helper that will just convert the data, which you can use anyway you want (example: in a popup, to display in a modal window, etc…).

<html>
<head>
    <title>Demo - Covnert JSON to CSV</title>
    <script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script>
    <script type="text/javascript" src="https://github.com/douglascrockford/JSON-js/raw/master/json2.js"></script>
    
    <script type="text/javascript">
		// JSON to CSV Converter
        function ConvertToCSV(objArray) {
            var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;
            var str = '';

            for (var i = 0; i < array.length; i++) {
                var line = '';
                for (var index in array[i]) {
                    if (line != '') line += ','

                    line += array[i][index];
                }

                str += line + '\r\n';
            }

            return str;
        }
		
		// Example
        $(document).ready(function () {
		
			// Create Object
            var items = [
				  { name: "Item 1", color: "Green", size: "X-Large" },
				  { name: "Item 2", color: "Green", size: "X-Large" },
				  { name: "Item 3", color: "Green", size: "X-Large" }];

			// Convert Object to JSON
			var jsonObject = JSON.stringify(items);
				
			// Display JSON
            $('#json').text(jsonObject);
			
			// Convert JSON to CSV & Display CSV
            $('#csv').text(ConvertToCSV(jsonObject));
        });	
    </script>
</head>
<body>
    <h1>
        JSON</h1>
    <pre id="json"></pre>
    <h1>
        CSV</h1>
    <pre id="csv"></pre>
</body>
</html>

Here is the output using the script and above.

JSON

Created with “JSON.stringify()” function from json.org.

[{"name":"Item 1","color":"Green","size":"X-Large"},{"name":"Item 2","color":"Green","size":"X-Large"},{"name":"Item 3","color":"Green","size":"X-Large"}]

CSV

Created with “ConvertToCSV()” function I created above.

Item 1,Green,X-Large
Item 2,Green,X-Large
Item 3,Green,X-Large