Why does forms with single input field submit upon pressing enter key in input

Behind the scenes

Hidden fields to the rescue

To stem this form submission action, add a hidden input field:

<input type="text" name="visibleInput">
<input type="hidden" name="hackPreventAutosubmit">  // our secret weapon
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This inconspicuous field isn't visible to users but follows the HTML norm - forms with more than one input field don't auto-submit on Enter key press in a text box.

Quirkiness of Internet Explorer

Old versions of IE, like IE6/7/8, have a bug causing forms to auto-reload on Enter. A mock field or separate input-type field stops this:

<input type="text" name="userInput">
<input type="text" style="display:none;" name="invisibleForceField"> // I'm here, but you can't see me!


Be mindful that visibility:hidden won't work, use display:none or aria-hidden="true" to maintain accessibility.

UX to the fore

Better UX is delivered by blocking default form submission when users press the Enter key using a JS event handler:

form.addEventListener('keypress', function(e) {
  if (e.keyCode === 13) {
    e.preventDefault();  // Don't even think about it, Enter key!
  }
});
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This prevents form submission and leaves the controls in users' hands.

Designing forms right

While designing, avoid unnecessary form tags if submission isn't intended. Alternatively, group radio buttons with the same name attribute so that users can select an option and press Enter to submit.

Embrace client-side scripting

To gain control over form actions, exploit simple client-side methods:

• Leash the enter key using JS or jQuery.
• Ensure consistency across browsers with timely tests, especially with older IE versions.

When to "Enter" to block submissions

Block Enter from submitting a form in occasions like:

• Single input autocomplete: Prevent form submission when users select an autocomplete suggestion.
• Search boxes: Allow users to fine-tune their query sans triggering a search.
• Incremental inputs: For inputs involved in minuscule operations or tweaks without submission.

Build forms strategically

These design cues will help evade inadvertent submissions:

• Multiple fields Architecture. Even a dummy input that's hidden can change behaviour.
• Button types: Keep submit buttons labeled, well-spotted to deter unintended form submissions.
• Instructional prompts: Guide users with inline instructions to avert confusion and accidental submissions.

Amalgamating a well-designed form structure with clever client-side scripting leads to a refined solution that meets UX quality standards and ensures cross-browser compatibility.