Question

我仍然在学习JavaScript，但尝试为某些最终用户构建一些表单验证，以便根据某些变量不能将字段设置为空。

这是我的相关代码。

＆＃13;

function validateForm() {
  var a = document.forms["myForm"]["Joint_1"].value;
  var b = document.forms["myForm"]["ID_1"].value;
  var c = document.forms["myForm"]["ID_2"].value;
  if (a == "Y" && b == "" && c == "") {
    console.log("Account is indicated to be joint, either one or both instances of ID is incomplete");
    return false;
  }
  if (a == "N" && b == "") {
    console.log("ID is incomplete for a single owner");
    return false;
  }
}

＆＃13;

.a {
  display: table-row;
}

.a div {
  display: table-cell;
  padding: 5px;
}

＆＃13;

<form name="myForm" onsubmit="return validateForm()" method="post">
  <div class="a">
    <div class='a'>
      <div>Joint Account?:</div>
      <div><select id="unit" size="1" name="Joint_1">
        <option disabled="disabled" selected="selected" value=""></option>
        <option value="Y">Y</option>
        <option value="N">N</option>
        </select></div>
    </div>
  </div>
  <div class="a">
    <div>ID:</div>
    <div><input type="text" name="ID_1" size="12" maxlength="12"></div>
  </div>
  <div class="a">
    <div>ID:</div>
    <div><input type="text" name="ID_2" size="12" maxlength="12"></div>
  </div>
  <div class='a'>
    <div><input type="submit" value="Save"></div>
    <div> <input type="reset" value="Reset"></div>
  </div>
</form>

＆＃13;

Joint_1将永远不会是空字符串，因为它将从其他地方继承其值。

该表单适用于Joint_1 == "Y"以及ID_1 == ""和ID_2 == ""。

但是，当Joint_1 == "Y"和ID_1或ID_2不是空字符串时，表单将提前而不是生成警报。必须在＆＃34; Y＆＃34;的实例中填写ID_1和ID_2。 Joint_1中的值。

有没有办法完成此操作，以便在Joint_1 == "Y"以及ID_1 == ""或ID_2 == ""时生成警报？我尝试使用or（||）运算符，但后来我在Joint_1 == "N"逻辑上失败了。

Answer 1

function validateForm() {
  var a = document.forms["myForm"]["Joint_1"].value,
      b = document.forms["myForm"]["ID_1"].value,
      c = document.forms["myForm"]["ID_2"].value;

  if (a === "Y" && (b === "" || c === "")) {
    alert("Account is indicated to be joint, either one or both instances of ID is incomplete");
    return false;
  } else if (a === "N" && b === "") {
    alert("ID is incomplete for a single owner");
    return false;
  }
}

作为最佳做法，您可能需要考虑使用===（身份）代替==（等于）进行比较 - {{ 3}}

验证表单 - 当一个变量=＆＃34; Y＆＃34;时，验证两个值不是空字符串？

1 个答案: