<!-- What is the error ? -->
<!doctype html>
<html>
<head>
<title>JS 5</title>
<script type="text/javascript">
//javascript function to change color according to input
function changeCol(){
var x=document.getEleme
我有一个角度的反应形式与作品大部分时间。但有时,随机的,我会犯一个错误
ERROR Error: Cannot find control with name: 'username'
at _throwError (forms.js:2337)
at setUpControl (forms.js:2245)
at FormGroupDirective.push../node_modules/@angular/forms/fesm5/forms.js.FormGroupDirective.addControl (forms.js:5471)
at F
在component.ts文件中我有:-
import {Component, OnInit, Input, Output, EventEmitter} from '@angular/core';
import * as moment_ from 'moment';
let moment=moment_;
type Moment=moment_.Moment;
export class DateTimeComponent implements OnInit {
private _ngModel: Moment= moment();
@Inp