dartpad example for clear console branch

index.html

<h1 id="header"></h1>
<button id="clicker"
        class="favorite styled"
        type="button">
    Click me to make console messages
</button>
<br/><br/><br/><br/>
<h3>Open the Console and click the clear console button 
  <image class="icon" src="https://timmaffett.github.io/clearconsole/pictures/clear-console.svg" /> 
  in the upper right to clear the console messages that you 
  are generating when clicking the <span class="styled">button</span> above .
</h3>

main.dart

import 'dart:html';

void main() {
  int clickCount=0;
  int extraConsoleMessages=0;
  final header = querySelector('#header');
  header?.text = "Hello, World!";
  
  final testButton = querySelector('#clicker');
  final dartSub = testButton!.onClick.listen((_) {
      clickCount++;
      print('You have clicked me $clickCount times now');
      for(int i=0;i<20;i++) {
        extraConsoleMessages++;
        print('   extra console message $extraConsoleMessages - try the clear console button!');
      }
    });

  for(int i=0;i<20;i++) {
    print('   some init console messages $i - try the clear console button!');
  }
}

styles.css

body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: absolute;
  width: 100%;
  height: 100%;
}

h1 {
  color: white;
  font-family: Arial, Helvetica, sans-serif;
}

h3 {
  width: 200px;
  font-family: Arial, Helvetica, sans-serif;
}

.icon {
  filter: invert(100%);
  width: 32px;
  height: 32px;
  margin: 0px 20px;
}

.styled {
    border: 0;
    line-height: 2.5;
    padding: 0 20px;
    font-size: 1rem;
    text-align: center;
    color: #fff;
    text-shadow: 1px 1px 1px #000;
    border-radius: 10px;
    background-color: cornflowerblue;
    background-image: linear-gradient(to top left,
                                      rgba(0, 0, 0, .2),
                                      rgba(0, 0, 0, .2) 30%,
                                      rgba(0, 0, 0, 0));
    box-shadow: inset 2px 2px 3px rgba(255, 255, 255, .6),
                inset -2px -2px 3px rgba(0, 0, 0, .6);
}

.styled:hover {
    background-color: olivedrab;
    transition: background-color 2.5s ease-out;
}

.styled:active {
    box-shadow: inset -2px -2px 3px rgba(255, 255, 255, .6),
                inset 2px 2px 3px rgba(0, 0, 0, .6);
}