Complete the abp.ajax document

docs/en/UI/AspNetCore/JavaScript-API/Ajax.md

@@ -10,7 +10,7 @@
 
 > While `abp.ajax` makes the AJAX call pretty easier, you typically will use the [Dynamic JavaScript Client Proxy](Dynamic-JavaScript-Client-Proxies.md) system to perform calls to your server side HTTP APIs. `abp.ajax` can be used when you need to perform low level AJAX operations.
 
-## Usage
+## Basic Usage
 
 `abp.ajax` accepts an options object that is accepted by the standard [$.ajax](https://api.jquery.com/jquery.ajax/#jQuery-ajax-settings). All the standard options are valid. It returns a [promise](https://api.jquery.com/category/deferred-object/) as the return value.
 
@@ -49,6 +49,8 @@ All kinds of errors are automatically handled by `abp.ajax`, unless you want to
 }
 ````
 
+The error message is directly shown to the user, using the `message` and `details` properties.
+
 ### Non-Standard Error Response & HTTP Status Codes
 
 It also handles errors even if the standard error format was not sent by the server. This can be case if you bypass the ABP exception handling system and manually build the HTTP response on the server. In that case, **HTTP status codes** are considered.
@@ -99,4 +101,50 @@ If you set `abpHandleError: false` and don't catch the error yourself, then the
 
 ## Configuration
 
-TODO
+`abp.ajax` has a **global configuration** that you can customize based on your requirements.
+
+### Default AJAX Options
+
+`abp.ajax.defaultOpts` object is used to configure default options used while performing an AJAX call, unless you override them. Default value of this object is shown below: 
+
+````js
+{
+    dataType: 'json',
+    type: 'POST',
+    contentType: 'application/json',
+    headers: {
+        'X-Requested-With': 'XMLHttpRequest'
+    }
+}
+````
+
+So, if you want to change the default request type, you can do it as shown below:
+
+````js
+abp.ajax.defaultOpts.type = 'GET';
+````
+
+Write this code before all of your JavaScript code. You typically want to place such a configuration into a separate JavaScript file and add it to the layout using the global [bundle](../Bundling-Minification.md).
+
+### Log/Show Errors
+
+The following functions can be overridden to customize the logging and showing the error messages:
+
+* `abp.ajax.logError` function logs errors using the [abp.log.error(...)](Logging.md) by default.
+* `abp.ajax.showError` function shows the error message using the [abp.message.error(...)](Message.md) by default.
+* `abp.ajax.handleErrorStatusCode` handles different HTTP status codes and shows different messages based on the code.
+* `abp.ajax.handleAbpErrorResponse` handles the errors sent with the standard ABP error format.
+* `abp.ajax.handleNonAbpErrorResponse` handles the non-standard error responses.
+* `abp.ajax.handleUnAuthorizedRequest` handles responses with `401` status code and redirect users to the home page of the application.
+
+**Example: Override the `logError` function**
+
+````js
+abp.ajax.logError = function(error) {
+    //...
+}
+````
+
+### Other Options
+
+* `abp.ajax.ajaxSendHandler` function is used to intercept the AJAX requests and add antiforgery token to the HTTP header. Note that this works for all AJAX requests, even if you don't use the `abp.ajax`.

docs/en/UI/AspNetCore/JavaScript-API/Logging.md

@@ -0,0 +1,3 @@
+# ASP.NET Core MVC / Razor Pages UI: JavaScript Logging API
+
+TODO