⚡ CYBER NOVEMBER SALE ⚡ 50% off any plan for 6 months, exclusive to new subscribers.

Join the Treehouse affiliate program and earn 25% recurring commission!

  • Treehouse Logo
  • Plans
    Chevron
    • For Individuals
    • For Businesses
    • For Schools
    • For Libraries
    • For Military
  • Library
    Chevron
    • All Courses
    • Tracks
    • College Credit
  • Techdegree
    Chevron
    • Overview
    • Front End Development
    • Full Stack JavaScript
    • Data Analysis
    • UX Design
    • Python
  • Community
    Chevron
    • Code Adventures
    • Discord
    • Forum
    • Success Stories
    • Treehouse Links
    • 100 Days of Code
  • Resources
    Chevron
    • Career Toolbox
    • CodeForward
    • Free Treehouse Near Me
    • Jobs
    • Blog
    • Support
    • About
  • For Individuals For Businesses For Schools For Libraries For Military
  • All Courses Tracks College Credit
  • Overview Front End Web Development Full Stack JavaScript Python Development Data Analysis UX Design
  • Code Adventures Discord Forum Success Stories Treehouse Links 100 Days of Code
  • Career Toolbox CodeForward Free Treehouse Near Me Jobs Blog Support About
  • Sign In
  • Free Trial
Instagram Twitter Facebook YouTube LinkedIn
    • Newest
      • Newest
      • Active
      • Unanswered
      • Featured
    • All Topics
      • All Topics
      • • General Discussion
      • • AI
      • • APIs
      • • Coding for Kids
      • • College Credit
      • • Computer Science
      • • CSS
      • • Data Analysis
      • • Databases
      • • Design
      • • Development Tools
      • • Digital Literacy
      • • Game Development
      • • Go Language
      • • HTML
      • • Java
      • • JavaScript
      • • Learning Resources
      • • Machine Learning
      • • No-Code
      • • PHP
      • • Professional Growth
      • • Python
      • • Quality Assurance
      • • React
      • • Ruby
      • • Security
      • • Swift
      • • Vibe Coding
  • Rifqi Fahmi
    Rifqi Fahmi
    23,164 Points

    Null value in this variables

    Posted December 16, 2015 3:33pm by Rifqi Fahmi
    Rifqi Fahmi
    23,164 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    0 Answers

  • pedro león
    PLUS
    pedro león
    Courses Plus Student 54 Points

    Porblem with $product

    Posted September 30, 2015 10:47pm by pedro león
    pedro león
    Courses Plus Student 54 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    1 Answer

  • Elena Paraschiv
    Elena Paraschiv
    9,938 Points

    Can someone explain me in detail this part?

    Posted September 24, 2015 9:21pm by Elena Paraschiv
    Elena Paraschiv
    9,938 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    4 Answers

  • Marcin Lipski
    Marcin Lipski
    9,947 Points

    How doest $_GET"id" variable know that "id" is a "product_id"?

    Posted June 16, 2015 11:39am by Marcin Lipski
    Marcin Lipski
    9,947 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    5 Answers

  • ibrahim el shahawy
    ibrahim el shahawy
    627 Points

    i am getting a redirect error

    Posted March 13, 2015 4:23am by ibrahim el shahawy
    ibrahim el shahawy
    627 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    2 Answers

  • SERGIO RODRIGUEZ
    SERGIO RODRIGUEZ
    17,532 Points

    header redirect not working on localhost.

    Posted December 19, 2014 3:22pm by SERGIO RODRIGUEZ
    SERGIO RODRIGUEZ
    17,532 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    6 Answers

  • Saad Aleem
    Saad Aleem
    6,089 Points

    Why use isset at all?

    Posted November 3, 2014 4:08pm by Saad Aleem
    Saad Aleem
    6,089 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    2 Answers

  • Steven Griffiths
    Steven Griffiths
    3,165 Points

    Understanding this if else code block + isset

    Posted October 30, 2014 4:02pm by Steven Griffiths
    Steven Griffiths
    3,165 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    2 Answers

  • Ian Hilton
    Ian Hilton
    6,223 Points

    How does isset check to see if a variable is loaded before the the code loads a variable ?

    Posted October 21, 2014 11:24pm by Ian Hilton
    Ian Hilton
    6,223 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    1 Answer

  • James Wong
    James Wong
    3,431 Points

    How to deal with "redirect loop" notifications in Chrome?

    Posted October 3, 2014 6:42am by James Wong
    James Wong
    3,431 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    2 Answers

  • Graham Patrick
    Graham Patrick
    8,294 Points

    PHP Error on if and else statements

    Posted September 4, 2014 8:46am by Graham Patrick
    Graham Patrick
    8,294 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    4 Answers

  • Luca Vicini
    PLUS
    Luca Vicini
    Courses Plus Student 8,594 Points

    exit(); after header("Location: shirts.php"); is it really necessary?

    Posted September 1, 2014 3:37pm by Luca Vicini
    Luca Vicini
    Courses Plus Student 8,594 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    3 Answers

  • Mohammed Ali Zaheer
    Mohammed Ali Zaheer
    11,787 Points

    shirt id display

    Posted July 23, 2014 4:24pm by Mohammed Ali Zaheer
    Mohammed Ali Zaheer
    11,787 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    1 Answer

  • Liban Shire
    PLUS
    Liban Shire
    Courses Plus Student 4,147 Points

    Confusing code when setting $_GET["id"] and $product

    Posted July 11, 2014 10:56pm by Liban Shire
    Liban Shire
    Courses Plus Student 4,147 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    1 Answer

  • Giovanni Valdenegro
    Giovanni Valdenegro
    13,871 Points

    Exit Function

    Posted July 2, 2014 10:43pm by Giovanni Valdenegro
    Giovanni Valdenegro
    13,871 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    3 Answers

  • Giovanni Valdenegro
    Giovanni Valdenegro
    13,871 Points

    If else statement sequence

    Posted July 2, 2014 7:41pm by Giovanni Valdenegro
    Giovanni Valdenegro
    13,871 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    4 Answers

  • Giovanni Valdenegro
    Giovanni Valdenegro
    13,871 Points

    Calling Variables

    Posted July 2, 2014 6:53pm by Giovanni Valdenegro
    Giovanni Valdenegro
    13,871 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    2 Answers

  • Darrel Lyons
    Darrel Lyons
    2,991 Points

    Arrays with $_POST

    Posted May 24, 2014 6:00pm by Darrel Lyons
    Darrel Lyons
    2,991 Points
    • PHP
    • Build a Simple PHP Application
    • Integrating with PayPal
    • Redirecting Invalid Shirt IDs

    8 Answers

Posting to the forum is only allowed for members with active accounts.
Please sign in or sign up to post.

    Treehouse

  • About
  • Blog
  • Careers
  • Community
  • Stories
  • Shop
  • Contact
  • Gift Card

See Full Catalogue

Techdegree

  • Front End Web Development
  • Full Stack JavaScript
  • Python Development
  • Data Analysis
  • UX Design

Tracks

  • Learn to Code for Beginners
  • Beginning Python
  • Beginning SQL
  • Beginning Java
  • ...see more

Courses

  • JavaScript Basics
  • Intro to HTML & CSS
  • Python Basics
  • CSS Layout
  • ...see more

Explore

  • Plans
  • Affiliates
  • Perks
  • Free Treehouse Near Me
  • Treehouse for Libraries
  • Treehouse for Businesses
  • Twitter
  • YouTube
  • Facebook
  • LinkedIn
  • Instagram
Terms & Conditions | Privacy

© 2025 Treehouse Island, Inc.