What does the v-bind directive do?

v-bind ties an HTML attribute to a JavaScript expression so the attribute updates reactively as that value changes.

<button v-bind:disabled="isButtonDisabled">Submit</button>

When isButtonDisabled is true, the button gets disabled attribute. When isButtonDisabled is false, the attribute is removed.

Shorthand: :disabled instead of v-bind:disabled

<button :disabled="email === ''">Submit</button>

Go deeper:

• Attribute Bindings (Vue docs) — v-bind, the : shorthand, and how boolean attributes like disabled are added/removed.