ajax - dataType

Question

What is the difference between    contentType   application json  charset utf-8   dataType   json     vs   contentType   application json   dataType   text

User · Answer

as per docs     json   Evaluates the response as JSON and returns a JavaScript object  In jQuery 1 4 the JSON data is parsed in a strict manner  any malformed JSON is rejected and a parse error is thrown   See json org for more information on proper JSON formatting    text   A plain text string

User · Answer

jQuery Ajax loader is not working well when you call two APIs simultaneously  To resolve this problem you have to call the APIs one by one using the isAsync property in Ajax setting  You also need to make sure that there should not be any error in the setting  Otherwise  the loader will not work  E g undefined content-type  data-type for POST PUT DELETE GET call

User · Answer

contentType is the HTTP header sent to the server  specifying a particular format  Example  I m sending JSON or XML dataType is you telling jQuery what kind of response to expect  Expecting JSON  or XML  or HTML  etc  The default is for jQuery to try and figure it out    The   ajax   documentation has full descriptions of these as well     In your particular case  the first is asking for the response to be in UTF-8  the second doesn t care   Also the first is treating the response as a JavaScript object  the second is going to treat it as a string   So the first would be   success  function data         get data  e g  data title      The second   success  function data      alert  Here s lots of data  just a string      data

User · Answer

ps  the answer given by Nick Craver is incorrect   contentType specifies the format of data being sent to the server as part of request it can be sent as part of response too  more on that later    dataType specifies the expected format of  data to be received by the client browser    Both are not interchangable    contentType is the header sent to the server  specifying the format of data i e the content of message body  being being to the server  This is used with POST and PUT requests  Usually when u send POST request  the message body comprises of passed in parameters like                                    Sample request   POST  search HTTP 1 1  Content-Type  application x-www-form-urlencoded   lt  lt other header gt  gt   name sam amp age 35                                   The last line above  name sam amp age 35  is the message body and contentType specifies it as application x-www-form-urlencoded since we are passing the form parameters in the message body  However we aren t limited to just sending the parameters  we can send json  xml     like this sending different types of data is especially useful with RESTful web services                                    Sample request   POST  orders HTTP 1 1 Content-Type  application xml  lt  lt other header gt  gt    lt order gt      lt total gt  199 02 lt  total gt      lt date gt December 22  2008 06 56 lt  date gt       lt  order gt                                    So the ContentType this time is  application xml  cause that s what we are sending  The above examples showed sample request  similarly the response send from the server can also have the Content-Type header specifying what the server is sending like this                                   sample response   HTTP 1 1 201 Created Content-Type  application xml  lt  lt other headers gt  gt    lt order id  233  gt      lt link rel  self  href  http   example com orders 133   gt      lt total gt  199 02 lt  total gt      lt date gt December 22  2008 06 56 lt  date gt       lt  order gt                                     dataType specifies the format of response to expect  Its related to Accept header  JQuery will try to infer it based on the Content-Type of the response                                    Sample request   GET  someFolder index html HTTP 1 1 Host  mysite org Accept  application xml  lt  lt other headers gt  gt                                    Above request is expecting XML from the server   Regarding your question   contentType   application json  charset utf-8   dataType   json     Here you are sending json data using UTF8 character set  and you expect back json data from the server  As per the JQuery docs for dataType       The json type parses the fetched data file as a JavaScript object and   returns the constructed object as the result data    So what you get in success handler is proper javascript object JQuery converts the json object for you   whereas  contentType   application json   dataType   text     Here you are sending json data  since you haven t mentioned the encoding  as per the JQuery docs      If no charset is specified  data will be transmitted to the server   using the server s default charset  you must decode this appropriately   on the server side    and since dataType is specified as text  what you get in success handler is plain text  as per the docs for dataType      The text and xml types return the data with no processing  The data is   simply passed on to the success handler

[jquery] $.ajax - dataType

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