在HTML中，可以使用required属性来实现简单的必填验证：

在Angular中，可以使用内置的FormBuilder和Validators：

  
  

    
Name is required.
    
Name must be at least 3 characters long.
    
Name cannot be longer than 10 characters.
  

import { FormBuilder, FormGroup, Validators } from '@angular/forms';

export class MyComponent {
  myForm: FormGroup;

  constructor(private formBuilder: FormBuilder) {
    this.myForm = this.formBuilder.group({
      name: ['', [Validators.required, Validators.minLength(3), Validators.maxLength(10)]],
    });
  }
}

在Bootstrap中，可以使用内置的表单控件和样式类来实现验证：

  Name
  
  
Name is required.