How to know if return data is Json or String in jQuery and PHP?

Question

Hi, I want to check in client side(jQuery) whether return data from a PHP function is Json object or String to assign different function.

Answer 1

In javascript, you can use typeof

Answer 2

Return data is always a string (i.e., a character sequence). But, if you tell jQuery you expect json response, it'll attempt to convert string into a javascript object for you.
There's no dedicated network protocol to transfer javascript objects over the internet.

Answer 3

jQuery's parseJson will generate an exception if the json is not in the correct format. You could wrap your call in a try catch block. (But remember that having exceptions in your normal code's flow is bad practice)

data = '{}';
try {
    json = $.parseJSON(data);
} catch (e) {
    // not json
}

Answer 4

try {
   jQuery.parseJSON( json )
   //must be valid JSON
} catch(e) {
    //must not be valid JSON    
}