Form submission basics in HTML - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What happens when a form with method="post" is submitted?

Consider a form with method="post". What is the main difference in how data is sent compared to method="get"?

A Data is sent in the URL query string, visible in the browser address bar.

B Data is sent only if JavaScript intercepts the form submission.

C Data is sent inside the HTTP request body, not visible in the URL.

D Data is sent as cookies automatically by the browser.

💡 Hint

Think about where the data is placed in the HTTP request for POST vs GET.

When a form uses method="post", the data is sent inside the HTTP request body. This keeps the data out of the URL, unlike GET where data appears in the URL query string.

📝 Syntax

intermediate

Which form attribute correctly specifies where to send the form data?

In an HTML form, which attribute defines the URL where the form data is sent after submission?

A action

B enctype

C target

D method

💡 Hint

It usually looks like a URL or path.

The action attribute specifies the URL where the form data is sent when the form is submitted.

❓ rendering

advanced

What is the visual result of this form code snippet?

Given this HTML form snippet, what will the user see in the browser?

HTML

<form action="/submit" method="get">
  <label for="email">Email:</label>
  <input type="email" id="email" name="email" required>
  <button type="submit">Send</button>
</form>

A A form with an email input but no label visible.

B A form with a text input box labeled 'Email:' and a button labeled 'Send'. The input accepts any text.

C A form with no visible input fields but a 'Send' button.

D A form with an email input box labeled 'Email:' and a button labeled 'Send'. The email input requires a valid email before submission.

💡 Hint

Look at the type and label elements.

The label is linked to the email input by for and id. The input type is email, so the browser enforces email format. The button text is 'Send'.

❓ selector

advanced

Which CSS selector styles only the submit button inside a form?

You want to style only the submit button inside any form on the page. Which CSS selector achieves this?

A form button[type="submit"]

B button.submit

C form > button

D input[type="submit"]

💡 Hint

Look for a selector that targets buttons with a specific attribute inside forms.

The selector form button[type="submit"] targets all button elements with type="submit" inside any form. Option A targets input elements, not button elements.

❓ accessibility

expert

What is the best way to make a form accessible for screen readers?

Which practice improves accessibility for screen reader users when filling out forms?

A Use placeholder text inside inputs instead of labels to save space.

B Use <code>label</code> elements properly linked to inputs with <code>for</code> and <code>id</code> attributes.

C Use only color changes to indicate required fields without text.

D Hide labels visually but do not link them to inputs.

💡 Hint

Think about how screen readers identify form fields.

Properly linked label elements ensure screen readers announce the label when the input is focused. Placeholders alone are not sufficient because they disappear when typing and are not always read by screen readers.

Practice

1. What does the action attribute in an HTML form specify?

easy

A. The type of input fields inside the form

B. The style of the form on the page

C. The method used to send the form data

D. The URL where the form data is sent after submission

Solution

1. Step 1: Understand the role of action attribute

   The action attribute tells the browser where to send the form data when the user submits the form.

2. Step 2: Differentiate from other attributes

   The method attribute controls how data is sent, not where. Styling and input types are unrelated to action.

3. Final Answer:

   The URL where the form data is sent after submission -> Option D

4. Quick Check:

   action = URL destination [OK]

Hint: Remember: action = destination URL for form data [OK]

Common Mistakes:

• Confusing action with method
• Thinking action controls form style
• Assuming action sets input types

2. Which of the following is the correct way to start a form that sends data using POST method to '/submit' URL?

easy

A.

B.

C.

D.

Solution

1. Step 1: Check attribute order and values

   Both action and method attributes are needed. The method should be 'post' and action should be '/submit'. The order of attributes does not affect correctness.

2. Step 2: Validate each option

   The <form method='post' action='submit'> has incorrect action (missing leading '/'). The <form action='/submit' method='post'> uses correct attribute names and values. The one with method='get' uses wrong method for POST. The one with method='submit' uses invalid method and action values.

3. Final Answer:

   <form action='/submit' method='post'> -> Option B

4. Quick Check:

   Correct syntax with POST method and action URL [OK]

Hint: Use for POST forms [OK]

Common Mistakes:

• Using 'submit' as method instead of 'post' or 'get'
• Mixing up method and action attribute values
• Using wrong attribute names

3. What happens when a user submits this form?

<form action='/send' method='get'>
  <input type='text' name='username' value='alice'>
  <input type='submit'>
</form>

medium

A. The form data is not sent because method is missing

B. The browser sends a POST request to '/send' with username in the body

C. The browser sends a GET request to '/send?username=alice'

D. The browser reloads the page without sending data

Solution

1. Step 1: Identify form method and action

   The form uses method='get' and action='/send', so data will be sent via URL query string to '/send'.

2. Step 2: Understand how GET sends data

   GET appends form data as key=value pairs in the URL. Here, username=alice is added to the URL.

3. Final Answer:

   The browser sends a GET request to '/send?username=alice' -> Option C

4. Quick Check:

   GET method sends data in URL [OK]

Hint: GET method sends data in URL query string [OK]

Common Mistakes:

• Thinking GET sends data in request body
• Assuming missing method means no data sent
• Confusing reload with form submission

4. Identify the error in this form code:

<form action='/submit' method='post'>
  <input type='text' name='email'>
  <input type='submit' value='Send'>
</form>

Why might this form cause accessibility issues?

medium

A. Missing <label> for the input field

B. Incorrect method attribute value

C. Submit button missing type attribute

D. Action attribute URL is invalid

Solution

1. Step 1: Check form attributes and elements

   The form uses correct action and method. The submit button has a value and defaults to type='submit'.

2. Step 2: Identify accessibility issue

   The input field lacks a <label> element, which helps screen readers and improves usability.

3. Final Answer:

   Missing <label> for the input field -> Option A

4. Quick Check:

   Labels improve accessibility [OK]

Hint: Always add <label> for inputs to help all users [OK]

Common Mistakes:

• Thinking submit button needs explicit type
• Assuming method='post' is wrong
• Believing action URL must be absolute

5. You want to create a form that sends user feedback to '/feedback' using POST. The form should have a text area labeled 'Comments' and a submit button labeled 'Send Feedback'. Which code snippet correctly implements this with accessibility and submission basics?

hard

A. \n Comments\n \n Send Feedback\n

B. \n \n \n

C. \n Comments\n \n Send Feedback\n

D. \n Comments\n \n \n

Solution

1. Step 1: Check form action and method

   The form must send data to '/feedback' using POST method. <form action='/feedback' method='post'>\n <label for='comments'>Comments</label>\n <textarea id='comments' name='comments'></textarea>\n <button type='submit'>Send Feedback</button>\n</form> and B have method='post', but B lacks label.

2. Step 2: Verify accessibility and button labeling

   <form action='/feedback' method='post'>\n <label for='comments'>Comments</label>\n <textarea id='comments' name='comments'></textarea>\n <button type='submit'>Send Feedback</button>\n</form> uses a <label> linked to the textarea with for and id, improving accessibility. The submit button is a <button> with clear text.

3. Step 3: Eliminate incorrect options

   <form action='/feedback' method='get'>\n <label>Comments</label>\n <textarea id='comments'></textarea>\n <button>Send Feedback</button>\n</form> uses GET method and missing name attribute on textarea, and label is not linked. <form action='/feedback'>\n <label for='comments'>Comments</label>\n <textarea id='comments' name='comments'></textarea>\n <input type='submit' value='Send Feedback'>\n</form> misses method attribute, so defaults to GET.

4. Final Answer:

   code snippet with proper action, method, label, and button -> Option A

5. Quick Check:

   Use POST + label + submit button for accessible form [OK]

Hint: Use label with for/id and method='post' for forms [OK]

Common Mistakes:

• Omitting method attribute defaults to GET
• Not linking label to input with for and id
• Using GET when POST is required