charging-cabinet/software/h5-uniapp/.agents/skills/vue-best-practices/reference/checkbox-true-false-value-form-submission.md

title, impact, impactDescription, type, tags

title	impact	impactDescription	type	tags
Checkbox true-value/false-value Not Submitted in Forms	MEDIUM	true-value and false-value attributes don't affect form submission - unchecked boxes send nothing	capability	vue3 v-model forms checkbox form-submission

Checkbox true-value/false-value Not Submitted in Forms

Impact: MEDIUM - Vue's true-value and false-value attributes only affect the JavaScript binding, NOT the actual form submission. Unchecked checkboxes are never included in form submissions by browsers, regardless of false-value.

This is a browser limitation, not a Vue issue. If you need to submit one of two values (like "yes"/"no" or "active"/"inactive"), use radio buttons instead of a checkbox.

Task Checklist

• Don't rely on false-value for form submissions - it won't be sent
• Use radio buttons when you need to submit one of exactly two values
• Remember true-value/false-value are for JavaScript state only
• For form submissions with custom values, handle the transformation server-side or in submit handler

Problem - false-value not submitted:

<script setup>
import { ref } from 'vue'

const status = ref('no')  // JavaScript value works correctly
</script>

<template>
  <form action="/api/update" method="POST">
    <!-- PROBLEM: When unchecked, nothing is submitted for this field -->
    <!-- Server receives no "status" field at all, not "no" -->
    <input
      type="checkbox"
      v-model="status"
      true-value="yes"
      false-value="no"
      name="status"
    >
    <label>Active</label>

    <!-- status.value correctly shows "yes" or "no" in Vue -->
    <!-- But form submission only sends "status=yes" when checked -->
    <!-- When unchecked, "status" field is completely missing -->
  </form>
</template>

Solution 1 - Use radio buttons for two-value submission:

<script setup>
import { ref } from 'vue'

const status = ref('no')
</script>

<template>
  <form action="/api/update" method="POST">
    <!-- CORRECT: Radio buttons always submit a value -->
    <label>
      <input type="radio" v-model="status" value="yes" name="status">
      Active
    </label>
    <label>
      <input type="radio" v-model="status" value="no" name="status">
      Inactive
    </label>

    <!-- Form always submits "status=yes" or "status=no" -->
  </form>
</template>

Solution 2 - Handle in submit handler (for SPA/AJAX):

<script setup>
import { ref } from 'vue'

const isActive = ref(false)

async function submitForm() {
  // Transform checkbox state to desired value before sending
  const payload = {
    status: isActive.value ? 'yes' : 'no'
  }

  await fetch('/api/update', {
    method: 'POST',
    body: JSON.stringify(payload)
  })
}
</script>

<template>
  <!-- For AJAX submission, checkbox is fine - transform in handler -->
  <input type="checkbox" v-model="isActive">
  <label>Active</label>

  <button @click="submitForm">Save</button>
</template>

Solution 3 - Hidden input fallback:

<template>
  <form action="/api/update" method="POST">
    <!-- Hidden input provides fallback value -->
    <input type="hidden" name="status" value="no">
    <!-- Checkbox overrides with "yes" when checked -->
    <input type="checkbox" name="status" value="yes" v-model="isActive">
    <label>Active</label>
  </form>
</template>

Reference

• Vue.js Form Input Bindings - Checkbox