Form Validation in Angular using formGroup

I am trying to make form validation in angular it is not working.

html:

<div>
    <form [formGroup]="form" action="javascript:void(0)" (submit)="send()" method="POST">
        <input formControlName="from_name" name="from_name" type="text"  placeholder="Full Name"/>
        <input formControlName="from_email" name="from_email" type="text"  placeholder="Email Address"/>
        <input formControlName="subject" name="subject" type="text" placeholder="{{this.property.Name}} in {{this.property.City}}"/>
        <textarea formControlName="message" name="message" type="text" placeholder="Enter your message"></textarea>
        <button id="clickit" class="button1" type="submit">Submit</button>
    </form>
</div>

in ts:

form: FormGroup = this.fb.group({
    from_name: ['', Validators.required],
    to_name: ['Admin', Validators.required],
    from_email: ['', Validators.required],
    subject: ['', Validators.required],
    message: ['', Validators.required],
});

if i click the button it is submitted even if i have some fields empty!