form onchange code example

Example 1: js html textbox on change

<!-- 
	You can use any of the following:
	onkeydown, onkeyup or onchange
 -->

<input type="text" onkeydown="keydownFunction()" 
onkeyup="keyupFunction()" onchange="changeFunction()">

Example 2: react how to pass the input target value

class NameForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: ''};

    this.handleChange = this.handleChange.bind(this);
  }

  handleChange(event) {
    this.setState({value: event.target.value});
  }

  render() {
    return (
      <form>
        <label>
          Name:
          <input type="text" value={this.state.value} onChange={this.handleChange} />
        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}

Example 3: javascript input value change

function updateInput(ish){
    document.getElementById("fieldname").value = ish;
}