提交时没有出现JavaScript警报

no JavaScript alert appearing on submit

本文关键字：JavaScript 警报 提交      更新时间：2023-09-26

尝试创建一个带有JavaScript验证的简单表单，以便在文本字段为空时提醒用户。当我在浏览器中打开保存的.html文件时，表单会出现，但当我单击提交时，没有出现JavaScript警报，我如何使此JavaScript功能工作并在提交时显示警报？

<!DOCTYPE html>
<html>
<head>
<script>
function validateForm() {
var errormessage= "";

    if (document.getElementsById('fullName').value ==""){errormessage += "First name must be filled out 'n";
        }
    }
    if (document.getElementsById('fullName').value ==""){errormessage += "First name must be filled out 'n";
        }
    }
    if (document.getElementsById('pNumber').value ==""){errormessage += "First name must be filled out 'n";
        }
    }
    if (document.getElementsById('eMail').value ==""){errormessage += "First name must be filled out 'n";
        }
    }
     if (document.getElementsById('aMessage').value ==""){errormessage += "First name must be filled out 'n";
        }
    }   
    if (errormessage !="") {
        alert(errormessage);
        return false;
        }
    }

</script>
</head>
<body>
<form method="post" action="#" onsubmit="return validateForm ()">
<fieldset>
    <label>Your Name: 
    <input type="text" id="fullName" name="fullName"></label>
    <br>
    <label>Your Phone Number: 
    <input type="text" id="pNumber" name="pNumber"></label>
    <br>
    <label>Your Email Address: 
    <input type="text" id="eMail" name="eMail"></label>
    <br>
    <label>Message: 
    <input type="text" id="aMessage" name="aMessage"></label>
    <br>
    <input type="submit" value="click to submit">
</fieldset>
</form>
</body>
</html>

有两个问题

1应该有getElementById。

2在if语句之后有两个}。只放一个}。

这将为你工作

function validateForm() {
    var errormessage= "";
    if (document.getElementById('fullName').value ==""){
        errormessage += "Name must be filled out 'n";
    }
    if (document.getElementById('pNumber').value ==""){
        errormessage += "Phone Number must be filled out 'n";
    }
    if (document.getElementById('eMail').value ==""){
        errormessage += "Email must be filled out 'n";
    }
    if (document.getElementById('aMessage').value ==""){
        errormessage += "Message must be filled out 'n";
    }   
    if (errormessage !="") {
        alert(errormessage);
        return false;
    }
}
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