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javascript - Why can't I get the input from the input box?

posted Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

javascript - Why can't I get the input from the input box?

I have made the following code to get the input from the input box. However, it can't get the input? Why?

var p = document.getElementById("paragraph");
var input = document.getElementById("input").value;
var foodname;

function changeP() {
  alert(input);
  if (input === "abc") {
    foodname = "Hey Yo!";
  } else if (input === "def") {
    foodname = "!oY yeH";
  } else {
    foodname = "N/A";
  }
  p.innerText = foodname;
}

<!DOCTYPE html>
<html>

<head>
  <meta charset="UTF-8">
  <title>Input Detecting</title>
</head>

<body>
  <p id="paragraph">Please type in the code in the following input bar. </p>
  <input id="input">
  <button onClick="changeP()">Confirm</button>
  <script src="JavaScript.js"></script>
</body>

</html>

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1 Reply

replyed Oct 17, 2021 by 深蓝 (71.8m points)

Because you can't get the input value but you can have it like this.

function changeP() {
var foodname;
  var input = document.getElementById("input").value;
    if (input === "abc") {
        foodname = "Hey Yo!";
    } else if (input === "def") {
        foodname = "!oY yeH";
    } else {
        foodname = "N/A";
    }
}

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