ajax post 跨域访问

php：

header('Access-Control-Allow-Origin:*');header('Access-Control-Allow-Methods:POST,GET');header('Access-Control-Allow-Credentials:true'); 

js:

$.ajax({    type: 'POST',    url: 'https://to.com/postHere.php',    crossDomain: true,    data: '{"some":"json"}',    dataType: 'json',    success: function(responseData, textStatus, jqXHR) {        var value = responseData.someKey;    },    error: function (responseData, textStatus, errorThrown) {        alert('POST failed.');    }});