AJAX responseXML

Question

I have a problem with an XML ajax answer .. I have this code from my callback function:

var lineString = responseXML.getElementsByTagName('linestring')[0].firstChild.nodeValue; 

However, a string can contain up to 4096 characters. The remaining characters are discarded.

I do not know what to use to get all the values ​​that the String string returns. its pretty big data, so I was thinking about using responseXml AJAX, BUT it turned out that it still can’t post everything.

My line consists of lines from a log file that I concatenated and just put a line separator. I need to get this data in my form, so after reading from php I will send it back through AJAX

Do you have any guys suggestions.

Answer 1

XML adds a lot of extra markup for most ajax requests. If you expect some kind of list with data entities, sending them in JSON format is the way to go.

I used JSON to get huge arrays of data.

First of all, JSON is just a Javascript object designation, meaning that an Ajax request requests a string that will actually be evaluated as a Javascript object.

Some browsers offer support for parsing JSON out of the box. Others need a little help. I used this little library to parse responseText in all the webapps I developed and had no problems with it.

Now that you know what JSON is and how to use it, here is what the PHP code looks like.

 $response = [ "success" => true, // I like to send a boolean value to indicate if the request // was valid and ok or if there was any problem. "records" => [ $dataEntity1, $dataEntit2 //.... ] ]; echo json_enconde($response ); 

Try it and see what it is. I used php 5.4 array declaration syntax because it is cool! :)

When requesting data through Ajax, you will do:

 var response ,xhr = getAjaxObject(); // XMLHttp or ActiveX or whatever. xhr.open("POST","your url goes here"); xhr.onreadystatechange=function() { if (xhr.readyState==4 && xhr.status==200) { try { response = JSON.parse(xhr.responseText); } catch (err) { response = { success : false, //other error data }; } if(response.success) { //your data should be in response // response.records should have the dataEntities console.debug(response.records); } } } 

Summary:

• JSON parsing needs a little help through the JSON2 library.
• PHP can send maps as JSON
• Boolean success is widely used as the success / unsuccessful flag

Alternatively, if you are in jQuery, you can simply set the dataType: "json" property in the $ .ajax call to get the JSON response in the callback.