Question

尝试使用JavaScript验证创建一个简单表单，以便在文本字段为空时提醒用户。当我在浏览器中打开已保存的.html文件时，表单会出现，但是当我点击提交时，没有出现任何JavaScript警报，如何使这个JavaScript功能工作并在提交时显示警告？

<!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>

Answer 1

有两个问题

1 应该有getElementById。

2 在}声明之后，你有两倍if。只需一个}。

这对您有用

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;
    }
}

提交时不会显示JavaScript警报

1 个答案: