用javascript创建正则表达式

Creating a regular expression in javascript

本文关键字：正则表达式 创建 javascript      更新时间：2023-09-26

我正在尝试进行表单验证，检查用户输入的输入是否与正则表达式匹配，而不是表单应该经过的验证。目前，我正在尝试验证名称字段，这样即使用户输入了至少2-15个字符，也可以包含空格。不应该是/^''w''s｛2,15｝$/；

<!DOCTYPE html>
<html>
   <head>
      <meta charset="UTF-8">
      <title>Bottles Form</title>
      <link rel="stylesheet" type="text/css" href="./css/form.css">
      <script type="text/javascript">
         function validFirstName() {
            var fName = document.getElementById("customerName").value;
            var regex = /^'w{2,15}$/;
            if (regex.test(fName)) {
               document.getElementById("firstNameAlert").innerHTML = "<span class='valid'>Valid</span>";
               return (true);
            } else {
               document.getElementById("firstNameAlert").innerHTML = "<span class='error'>Error. First Name must be within 2 to 15 characters</span>";
              return (false);
            }
         }
         function formCalculator() {
            const SALESTAX = .0825;
            var userName = document.getElementById("customerName").value;
            var quantity = document.getElementById("quantityBottle").value;
            var costBottle = document.getElementById("costBottle").value;
            var totalBottle = quantity * costBottle;
            var discount = 0;
            var discountedTotal = 0;
            var taxTotal = totalBottle * SALESTAX;
            var orderTotal = totalBottle + taxTotal;
            //var orderWithDiscount = discountedTotal + taxTotal;
           if(parseInt(quantity) > 10 && parseInt(quantity) <= 19) {
              discount = .10;
              totalBottle = totalBottle - (totalBottle * discount);
           }
           orderTotal.value = "$" + orderTotal.toFixed(2);
           document.getElementById("result").innerHTML = "Hello " + userName + " - Your order of " + quantity + " bottles, costs $" + orderTotal.toFixed(2) + ", plus tax.";
        }
     </script>
  </head>
  <body>
     <h1>Bottles Form</h1>
     <form action="" method="post" enctype="multipart/form-data" name="wigetCalc">
        <input name="customerName" id="customerName" type="text" size="20"  onblur="validFirstName();"/>&nbsp;-&nbsp;<span id="firstNameAlert">First Name</span><br />
        <input name="quantityBottle" id="quantityBottle" type="text" value="0" size="20" maxlength="3" />&nbsp;Bottle Order Quantity<br />
        <input name="costBottle" id="costBottle" type="text" value="5.31" size="20" readonly="readonly" />&nbsp;Bottle Cost<br />
        <p class ="coloredBox" onclick="formCalculator();">Submit</span></p>
        <div id="result"></div>
     </form>
   </body>
</html>

量化符匹配前面的标记，这是当前正则表达式中的一个空格。因此，您的正则表达式匹配一个后面跟着2-15个空格的字母。您希望使用字符集来匹配字母和空格（方括号）的任何组合。

/^['w's]{2,15}$/

请参阅：http://www.regular-expressions.info/charclass.html

为什么不直接使用长度？

var fName = document.getElementById("customerName").value;
if (fName.length >= 2 && fName.length <= 15) {
    document.getElementById("firstNameAlert").innerHTML = "<span class='valid'>Valid</span>";
} else {
    document.getElementById("firstNameAlert").innerHTML = "<span class='error'>Error. First Name must be within 2 to 15 characters</span>";
}
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