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Passing HTML input value as a JavaScript Function Parameter

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别跟我提以往
别跟我提以往 2020-12-13 15:52

I am new to JavaScript, and I\'m trying to figure out how to pass user-inputted values as a parameter to a JavaScript function. Here is my code:
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7条回答
  • 陌清茗
    2020-12-13 16:09

    You can get the values with use of ID. But ID should be Unique.

    <body>
<h1>Adding 'a' and 'b'</h1>
<form>
  a: <input type="number" name="a" id="a"><br>
  b: <input type="number" name="b" id="b"><br>
  <button onclick="add()">Add</button>
</form>
<script>
  function add() {
    a = $('#a').val();
    b = $('#b').val();
    var sum = a + b;
    alert(sum);
  }
</script>
</body>
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  • 余生分开走
    2020-12-13 16:11 
       <form action="" onsubmit="additon()" name="form1" id="form1">
      a: <input type="number" name="a" id="a"><br>
      b: <input type="number" name="b" id="b"><br>
      <input type="submit" value="Submit" name="submit">
   </form>
  <script>
      function additon() 
      {
           var a = document.getElementById('a').value;
           var b = document.getElementById('b').value;
           var sum = parseInt(a) + parseInt(b);
           return sum;
      }
  </script>
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  • 庸人自扰
    2020-12-13 16:12

    Firstly an elements ID should always be unique. If your element IDs aren't unique then you would always get conflicting results. Imagine in your case using two different elements with the same ID.

    <form>
  a: <input type="number" name="a" id="a"><br>
  b: <input type="number" name="b" id="b"><br>
  <button onclick="add()">Add</button>
</form>

<script>
  function add() {
    var a = document.getElementById('a').value;
    var b = document.getElementById('b').value;

    var sum = parseInt(a) + parseInt(b);
    alert(sum);
  }
</script>
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  • 不思量自难忘°
    2020-12-13 16:16

    do you use jquery? if then:

    $('#xx').val();

    or use original javascript(DOM)

    document.getElementById('xx').value

    or

    xxxform.xx.value;

    if you want to learn more, w3chool can help you a lot.

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  • 面向向阳花
    2020-12-13 16:16

    Use this it will work,

    <body>
<h1>Adding 'a' and 'b'</h1>
<form>
  a: <input type="number" name="a" id="a"><br>
  b: <input type="number" name="b" id="a"><br>
  <button onclick="add()">Add</button>
</form>
<script>
  function add() {
    var m = document.getElementById("a").value;
    var n = document.getElementById("b").value;
    var sum = m + n;
    alert(sum);
  }
</script>
</body>
    0 讨论(0)
  • 情话喂你
    2020-12-13 16:23

    1 IDs are meant to be unique

    2 You dont need to pass any argument as you can call them in your javascript

    <form>
  a: <input type="number" name="a" id="a"><br>
  b: <input type="number" name="b" id="b"><br>
  <button onclick="add()">Add</button>
</form>
<script>
  function add() {
    var a = document.getElementById('a').value;
    var b = document.getElementById('b').value;
    var sum = a + b;
    alert(sum);
  }
</script>
    0 讨论(0)
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