p3.component.ts

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

@Component({
  selector: 'app-p3',
  templateUrl: './p3.component.html',
  styleUrls: ['./p3.component.css']
})
export class P3Component implements OnInit {

  widthLength = '1024';
  heightLength = '768';
  imageUrl = 'http://lorempixel.com//{{widthLength}}/{{heightLength}}/';

  showPic() {
    if (this.widthLength !== null && this.heightLength !== null &&
      this.widthLength !== undefined && this.heightLength !== undefined) {
      this.imageUrl = "http://lorempixel.com/" + this.widthLength + "/" + this.heightLength + "/";
    } else {
      alert("長度或高度不得為空!");
    }
  }

  constructor() { }

  ngOnInit() { }

}