fix(checkbox): use a native input to fix a11y issues with axe and screen readers (#22402)

fixes #21644
fixes #20517
fixes #17796

core/src/components/checkbox/checkbox.tsx

@@ -2,7 +2,7 @@ import { Component, ComponentInterface, Element, Event, EventEmitter, Host, Prop
 
 import { getIonMode } from '../../global/ionic-global';
 import { CheckboxChangeEventDetail, Color, StyleEventDetail } from '../../interface';
-import { findItemLabel, renderHiddenInput } from '../../utils/helpers';
+import { getAriaLabel, renderHiddenInput } from '../../utils/helpers';
 import { createColorClasses, hostContext } from '../../utils/theme';
 
 /**
@@ -22,7 +22,7 @@ import { createColorClasses, hostContext } from '../../utils/theme';
 export class Checkbox implements ComponentInterface {
 
   private inputId = `ion-cb-${checkboxIds++}`;
-  private buttonEl?: HTMLElement;
+  private focusEl?: HTMLElement;
 
   @Element() el!: HTMLElement;
 
@@ -54,11 +54,11 @@ export class Checkbox implements ComponentInterface {
   @Prop() disabled = false;
 
   /**
-   * The value of the toggle does not mean if it's checked or not, use the `checked`
+   * The value of the checkbox does not mean if it's checked or not, use the `checked`
    * property for that.
    *
-   * The value of a toggle is analogous to the value of a `<input type="checkbox">`,
-   * it's only used when the toggle participates in a native `<form>`.
+   * The value of a checkbox is analogous to the value of an `<input type="checkbox">`,
+   * it's only used when the checkbox participates in a native `<form>`.
    */
   @Prop() value = 'on';
 
@@ -68,12 +68,12 @@ export class Checkbox implements ComponentInterface {
   @Event() ionChange!: EventEmitter<CheckboxChangeEventDetail>;
 
   /**
-   * Emitted when the toggle has focus.
+   * Emitted when the checkbox has focus.
    */
   @Event() ionFocus!: EventEmitter<void>;
 
   /**
-   * Emitted when the toggle loses focus.
+   * Emitted when the checkbox loses focus.
    */
   @Event() ionBlur!: EventEmitter<void>;
 
@@ -109,12 +109,15 @@ export class Checkbox implements ComponentInterface {
   }
 
   private setFocus() {
-    if (this.buttonEl) {
-      this.buttonEl.focus();
+    if (this.focusEl) {
+      this.focusEl.focus();
     }
   }
 
-  private onClick = () => {
+  private onClick = (ev: Event) => {
+    ev.preventDefault();
+    ev.stopPropagation();
+
     this.setFocus();
     this.checked = !this.checked;
     this.indeterminate = false;
@@ -129,14 +132,11 @@ export class Checkbox implements ComponentInterface {
   }
 
   render() {
-    const { inputId, indeterminate, disabled, checked, value, color, el } = this;
-    const labelId = inputId + '-lbl';
+    const { color, checked, disabled, el, indeterminate, inputId, name, value } = this;
     const mode = getIonMode(this);
-    const label = findItemLabel(el);
-    if (label) {
-      label.id = labelId;
-    }
-    renderHiddenInput(true, el, this.name, (checked ? value : ''), disabled);
+    const { label, labelId, labelText } = getAriaLabel(el, inputId);
+
+    renderHiddenInput(true, el, name, (checked ? value : ''), disabled);
 
     let path = indeterminate
       ? <path d="M6 12L18 12" part="mark" />
@@ -151,10 +151,10 @@ export class Checkbox implements ComponentInterface {
     return (
       <Host
         onClick={this.onClick}
-        role="checkbox"
-        aria-disabled={disabled ? 'true' : null}
+        aria-labelledby={label ? labelId : null}
         aria-checked={`${checked}`}
-        aria-labelledby={labelId}
+        aria-hidden={disabled ? 'true' : null}
+        role="checkbox"
         class={createColorClasses(color, {
           [mode]: true,
           'in-item': hostContext('ion-item', el),
@@ -167,14 +167,18 @@ export class Checkbox implements ComponentInterface {
         <svg class="checkbox-icon" viewBox="0 0 24 24" part="container">
           {path}
         </svg>
-        <button
-          type="button"
-          onFocus={this.onFocus}
-          onBlur={this.onBlur}
-          disabled={this.disabled}
-          ref={btnEl => this.buttonEl = btnEl}
-        >
-        </button>
+        <label htmlFor={inputId}>
+          {labelText}
+        </label>
+        <input
+          type="checkbox"
+          aria-checked={`${checked}`}
+          disabled={disabled}
+          id={inputId}
+          onFocus={() => this.onFocus()}
+          onBlur={() => this.onBlur()}
+          ref={focusEl => this.focusEl = focusEl}
+        />
       </Host>
     );
   }