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Web Development

827Fetch API Fundamentals and Basic GET Requests
828The Response Object: Properties and Status Handling
829Response Body Methods: json(), text(), blob(), and More
830Making POST Requests with JSON Data
831The Request Object and Request Configuration
832Setting and Managing Request Headers
833Handling Different HTTP Methods: PUT, PATCH, DELETE
834Request Credentials: Cookies and Authentication
835Request Modes: cors, no-cors, same-origin, navigate
836Error Handling: Network vs HTTP Errors
837Aborting Requests with AbortController
838Request Timeouts with AbortSignal.timeout()
839Streaming Response Bodies with ReadableStream
840Sending Form Data: multipart/form-data Uploads
841Request Caching: cache, reload, no-cache, force-cache
842Request Integrity and Subresource Integrity
843Referrer Policy and Privacy Controls
844Fetch API Best Practices and Patterns
845Request Object Basics
846Creating Request Objects
847Request Methods and URL
848Request Headers
849Request Body
850Request Body Methods
851Request Credentials and Mode
852Request Cache and Redirect
853Response Object Basics
854Response Status and StatusText
855Response Headers
856Response Body Methods
857Creating Custom Responses
858Response Cloning
859Response Type and URL
860What is CORS and Why It Exists
861Simple vs Preflight Requests
862The OPTIONS Preflight Request
863Access-Control-Allow-Origin Header
864Credentials and CORS
865Custom Headers and Preflight
866Allowed HTTP Methods
867Exposing Response Headers
868CORS Error Messages
869Debugging CORS Issues
870Development Proxies for CORS
871CORS Best Practices
872Real-Time Communication Patterns
873Server-Sent Events Fundamentals
874Creating an SSE Connection
875SSE Event Types and Data Format
876SSE Connection Lifecycle
877WebSocket Fundamentals
878Creating a WebSocket Connection
879Sending and Receiving WebSocket Messages
880WebSocket Error Handling and Reconnection
881WebSocket Security Considerations
882Choosing Between SSE and WebSockets
883Real-Time Data Patterns

Web Development

827Fetch API Fundamentals and Basic GET Requests
828The Response Object: Properties and Status Handling
829Response Body Methods: json(), text(), blob(), and More
830Making POST Requests with JSON Data
831The Request Object and Request Configuration
832Setting and Managing Request Headers
833Handling Different HTTP Methods: PUT, PATCH, DELETE
834Request Credentials: Cookies and Authentication
835Request Modes: cors, no-cors, same-origin, navigate
836Error Handling: Network vs HTTP Errors
837Aborting Requests with AbortController
838Request Timeouts with AbortSignal.timeout()
839Streaming Response Bodies with ReadableStream
840Sending Form Data: multipart/form-data Uploads
841Request Caching: cache, reload, no-cache, force-cache
842Request Integrity and Subresource Integrity
843Referrer Policy and Privacy Controls
844Fetch API Best Practices and Patterns
845Request Object Basics
846Creating Request Objects
847Request Methods and URL
848Request Headers
849Request Body
850Request Body Methods
851Request Credentials and Mode
852Request Cache and Redirect
853Response Object Basics
854Response Status and StatusText
855Response Headers
856Response Body Methods
857Creating Custom Responses
858Response Cloning
859Response Type and URL
860What is CORS and Why It Exists
861Simple vs Preflight Requests
862The OPTIONS Preflight Request
863Access-Control-Allow-Origin Header
864Credentials and CORS
865Custom Headers and Preflight
866Allowed HTTP Methods
867Exposing Response Headers
868CORS Error Messages
869Debugging CORS Issues
870Development Proxies for CORS
871CORS Best Practices
872Real-Time Communication Patterns
873Server-Sent Events Fundamentals
874Creating an SSE Connection
875SSE Event Types and Data Format
876SSE Connection Lifecycle
877WebSocket Fundamentals
878Creating a WebSocket Connection
879Sending and Receiving WebSocket Messages
880WebSocket Error Handling and Reconnection
881WebSocket Security Considerations
882Choosing Between SSE and WebSockets
883Real-Time Data Patterns

← Web Development

Lesson 862 of 2,982·15. Browser NetworkingPro lesson

The OPTIONS Preflight Request

Understanding how browsers send preflight OPTIONS requests before actual cross-origin requests.

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