Single vs. Double Quotes in jQuery.parseJSON

When using jQuery's parseJSON method, users may encounter differences in behavior depending on whether single or double quotes are used to enclose the JSON string. In this article, we'll explore these differences.

Double Quotes: The Standard Approach

According to the JSON standard, double quotes are considered the preferred method for enclosing JSON strings. This is also the case with jQuery's parseJSON method, which expects JSON strings to be in double quotes. The following example illustrates this:

var obj1 = jQuery.parseJSON('{"orderedList": "true"}');
document.write("obj1 "   obj1.orderedList); // Outputs "obj1 true"

Single Quotes: An Unsupported Format

In contrast, single quotes are not considered a valid JSON string format. As a result, using single quotes when calling parseJSON will lead to an error. The following example demonstrates this:

var obj2 = jQuery.parseJSON("{'orderedList': 'true'}");
document.write("obj2 "   obj2.orderedList); // Outputs "obj2 undefined"

This behavior is not specific to jQuery. Rather, it is rooted in the JSON standard itself, which mandates the use of double quotes for string values. Therefore, regardless of the JavaScript toolkit being used, it is essential to use double quotes when working with JSON strings.