Javascript - 如何使用 RegExp 识别模式

Question

当用户输入错误时，提交按钮应该弹出一条警告消息，指出邮政编码和邮政编码的模式错误。但我似乎无法让它发挥作用。我不想在表单中使用“pattern=”。我想显示一个警报框。我需要使用 RegExp 方法。有什么想法吗？

这是我的代码:

                <script>
                function validation(){
                  var icn = document.getElementById("icno").value;
                  var postcode = document.getElementById("pstcode").value;
                  var regexp = new RegExp(icn,"\d{6}-\d{2}-\d{4}");
          var regexp1 = new RegExp(postcode,"[0-9]{5}");

                  if (regexp.exec(icn)){
            return true;
                  }
                  else{
            alert("Please enter your IC correctly")
                  }

          if (regexp1.exec(postcode)){
            return true;
                  }
                  else{
            alert("Please enter your postcode correctly")
                  }
                }
                </script>
            </body>
    </html>

Answer 1

如果您想使用 RegExp 和 .exec，请尝试以下操作:

function validation() {
  var icn = document.getElementById("icno").value;
  var postcode = document.getElementById("pstcode").value;
  var regexp = new RegExp(/\d{6}-\d{2}-\d{4}/);
  var regexp1 = new RegExp(/[0-9]{5}/);

  if (regexp.exec(icn) !== null) {
    return true;
  } else {
    alert("Please enter your IC correctly")
  }

  if (regexp1.exec(postcode) !== null) {
    return true;
  } else {
    alert("Please enter your postcode correctly")
  }
}

<form id="myForm" onsubmit="validation()">
  <fieldset>
    <legend>Regular Expression</legend>

    <label for="name">Name</label>
    <input type="text" id="name" size="30" placeholder="Enter name.">
    </br>
    </br>

    <label for="icno">IC No</label>
    <input type="text" id="icno" size="15" placeholder="E.g. 889601-11-6575">
    </br>
    </br>

    <label for="address">Address 1</label>
    <input type="text" id="address" size="30" placeholder="Address 1">
    </br>
    </br>

    <label for="address">Address 2</label>
    <input type="text" id="address" size="30" placeholder="Address 2">
    </br>
    </br>

    <label for="postcode">Postcode</label>
    <input type="text" id="pstcode" size="8" placeholder="E.g 21030">
    </br>
    </br>

    <input type="submit" value="Submit" id="btnSubmit">
  </fieldset>
</form>

但我建议你使用.test，很简单:

function validation() {
   var icn = document.getElementById("icno").value;
   var postcode = document.getElementById("pstcode").value;

   if (/\d{6}-\d{2}-\d{4}/.test(icn)) {
     return true;
   } else {
     alert("Please enter your IC correctly")
   }

   if (/[0-9]{5}/.test(postcode)) {
     return true;
   } else {
     alert("Please enter your postcode correctly")
   }
 }