jQuery .ajax调用返回JSON ParseError甚至认为JSON似乎是正确的？

I'm getting a ParseError even though my JSON validates on jsonlint.com.

Here is the jQuery code:

$.ajax({
    url: path,
    type: 'GET',
    data: {},
    cache: false,
    dataType: 'json',
    contentType: 'application/json; charset=utf-8',                  
    success: function (data) {
        var a = 'breakpoint here doesn't activate';
    },
    error: function (x, y, z) {
        var b = 'code execution stops at a breakpoint here.';
    }
});

Here is the PHP code that is being called:

function getAllAnswersToHitViaAjax($theJobName) {
    $testData[0] = 'testing123';
    $encodedData = json_encode($testData);
    echo $encodedData;
    return;
}

This comes back to a breakpoint set in the error: function of my .ajax call. Parameter Y is set to "parseerror", and x.responseText =

["testing123"] 

I've been looking into this for hours so far. I've looked at many relevant StackOverflow posts, but none have solutions that work in this case.

How can I get a success response from this .ajax call?

Thanks very much in advance to all for any info.

There's nothing visibly wrong with your code, and it works fine when I try it on my local machine. However, your comment above is a big clue:

I just looked at the z param in the Safari console, and found this:"undefined is not a function (evaluating 'JSON.parse(a+"")')" How could that be happening?

It could happen if some code somewhere uses "JSON" as a global variable name, hiding the built-in window.JSON object.

Please use

 $.ajax({
    url: path,
    type: 'GET',
    cache: false,
    dataType: 'json',
    contentType: 'application/json; charset=utf-8',                  
    success: function (data) {
        var a = 'breakpoint here doesn\'t activate';
    },
    error: function (x, y, z) {
        var b = 'code execution stops at a breakpoint here.';
    }
});

and in your PHP CODE Paste this code.

function getAllAnswersToHitViaAjax($theJobName) {
    $testData[0] = 'testing123';
    $encodedData = $testData;
    echo json_encode($encodedData);
    exit;
}

May be after digging more in your code I assume that in your PHP code you were not passing data properly. Please use exit or die method to pass data back to ajax. Please check.

Check for Notice or Warning in your php code, if their is any then remove that and then try. Hop this will help you.

JavaScript allows either single or double quotes for strings, but JSON only allows double quotes. See http://www.json.org/

See also jQuery.parseJSON single quote vs double quote

Just Use

function getAllAnswersToHitViaAjax($theJobName) {
   $testData[0] = 'testing123';
   echo json_encode($testData);
}

Then in your AJAX you can do

$.ajax({
 url: path,
 type: 'GET',
 dataType: 'json'
 success: function(data){
    for (var i = 0; i < data.length; i++) {
        //DO YOUR STUFF          
    }
 }
});

Try with the below code,

    function getAllAnswersToHitViaAjax($theJobName) {
    $testData[0] = 'testing123';
    echo json_encode($testData);
    die();
    }

    $.ajax({
    url: path,
    type: 'GET',
    dataType: 'json'
    success: function(data){
        console.log(data);
        var result = JSON.parse(data);
        console.log(result);
    }
    });