p4.component.ts

import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'app-p4',
  templateUrl: './p4.component.html',
  styleUrls: ['./p4.component.css']
})
export class P4Component implements OnInit {

  number = '';
  value2: any;

  addNumber(inputRef: HTMLInputElement): void {
    console.log(inputRef.value);
    inputRef.value = '';

    this.value2 = new Number(inputRef.value);

    if (
      this.value2 > 0
    ) {
      alert('輸入正確');
    } else {
    alert('請輸入大於0的數字');
    }
  }

  addNumber2(inputRef: HTMLInputElement): void {
    console.log(inputRef.value);
    inputRef.value = '';

    this.value2 = new Number(inputRef.value);

    if (
      this.value2 !== Number
    ) {
      alert('只能輸入數字');
    } else {
    alert('輸入正確');
    }
  }

  addNumber3(inputRef: HTMLInputElement): void {
    console.log(inputRef.value);
    inputRef.value = '';

    this.value2 = new Number(inputRef.value);

    if (
      this.value2 !== Number
    ) {
      alert('欄位只能輸入英文兩碼 + 數字三碼');
    } else {
    alert('輸入正確');
    }
  }


  constructor() { }

  ngOnInit() {
  }

}