从Javascript中的行html中获取值

<input type="text" id="myInput">
<button onclick="getValue()">获取值</button>

<script>
function getValue() {
  var value = document.getElementById("myInput").value;
  console.log(value);
}
</script>

<input type="text" id="myInput">
<button onclick="getValue()">获取值</button>

<script>
function getValue() {
  var value = document.querySelector("#myInput").value;
  console.log(value);
}
</script>

<input type="text" class="myInput">
<button onclick="getValue()">获取值</button>

<script>
function getValue() {
  var value = document.getElementsByClassName("myInput")[0].value;
  console.log(value);
}
</script>

<input type="text" name="myInput">
<button onclick="getValue()">获取值</button>

<script>
function getValue() {
  var value = document.getElementsByTagName("input")[0].value;
  console.log(value);
}
</script>