如何验证输入类型文本是否为空-PHP

我正在尝试制作一个联系人表单，需要对input type=text进行验证，但是，它似乎有一些错误，我找不到。你能帮助我吗？代码如下：

    <td>
Name*:<input type="text" name="name" id='name2' class="name1" />
</td>
<td>
Email*:<input type='text' name="email" class="email1" id='email2'/>
</td>
</tr>
<tr>
<td colspan="2" rowspan="2">
Message*: <br />

<textarea name='msg' style="float:right;" class="msg1" id='msg2'>
</textarea>
</td>

在这里：

<?PHP
$nml = strlen($_POST['name']);
$eml = strlen($_POST['email']);
$msgl = strlen($_POST['msg']);

if(isset($_GET['sent'])) {
    if($nml<1) { 
    if($eml<1) {
    if($msgl<1) {   
        exit("<script>document.getElementById('name2').style.borderColor='red'; document.getElementById('email2').style.borderColor='red'; document.getElementById('msg2').style.borderColor='red';</script><center><font color='red'>Name*, Email* and Message* fields are required</font></center>");
    }
    exit("<script>document.getElementById('name2').style.borderColor='red'; document.getElementById('email2').style.borderColor='red';</script><center><font color='red'>Name* and Email* fields are required</font></center>");
    }
    exit("<script>document.getElementById('name2').style.borderColor='red'; <center><font color='red'>Name* field is required</font></center>");
    }
    if($eml<1) {
        if($msgl<1) {
            if($nml<1) {
        exit("<script>document.getElementById('email2').style.borderColor='red'; document.getElementById('name2').style.borderColor='red'; document.getElementById('msg2').style.borderColor='red';</script><center><font color='red'>Email*, Name * and Message* fields are required</font></center>");
            }
            exit("<script>document.getElementById('email2').style.borderColor='red'; document.getElementById('msg2').style.borderColor='red';</script><center><font color='red'>Email* and Message* fields are required</font></center>");
    }
        exit("<script>document.getElementById('email2').style.borderColor='red';</script><center><font color='red'>Email* field is required</font></center>");
    }
    if($msgl<1) {
        if($nml<1) {
            if($eml<1) {
                exit("<script>document.getElementById('msg2').style.borderColor='red'; document.getElementById('name2').style.borderColor='red'; document.getElementById('email2').style.borderColor='red';</script><center><font color='FF0000'>Message*, Name* and Email* Fields are required</font></center>");
            }
            exit("<script>document.getElementById('msg2').style.borderColor='red'; document.getElementById('name2').style.borderColor='red';</script><center><font color='FF0000'>Message* and Name* Fields are required</font></center>");
        }
        exit("<script>document.getElementById('msg2').style.borderColor='red';</script><center><font color='FF0000'>Message* Field is required</font></center>");
    }

}
?>

---

请帮我修一下，我试了很多次，但就是修不好。这对我来说太难了

您的代码的问题是这部分逻辑：

if($nml<1) { 
    if($eml<1) {
        if($msgl<1) {   
            exit(/* simplified for clarity */);
        }
        exit(/* simplified for clarity */);
    }
    exit(/* simplified for clarity */);
}

如果每条消息需要不同，则使用单独的If语句，如下所示：

if($nml<1) { 
    exit(/* simplified for clarity */);
}

if($eml<1) {
    exit(/* simplified for clarity */);
}

if($msgl<1) {   
    exit(/* simplified for clarity */);
}

相反，使用-检查索引是否已设置，以及是否为空，这将防止抛出通知

if(empty($_POST['name']) { 
    exit(/* simplified for clarity */);
}

---

对post变量使用trim函数，例如$nml=strlentrim$\u post['name']

使用它：

<?php

if(isset($_POST['sent'])) {

    $nml = strlen($_POST['name']);
    $eml = strlen($_POST['email']);
    $msgl = strlen($_POST['msg']);

    if(empty($nml)) { 
        echo "<script>document.getElementById('name2').style.borderColor='red'; </script><center><font color='red'>Name* fields is required</font></center><br>";
    }
    if(empty($eml)) {
        echo "<script>document.getElementById('email2').style.borderColor='red';</script><center><font color='red'>Email* fields is required</font></center><br>";
    }
    if(empty($msgl)) {   
        echo "<script>document.getElementById('msg2').style.borderColor='red'; <center><font color='red'>Message* field is required</font></center><br>";    
    }

    if(empty($nml) || empty($eml) || empty($msgl)) {
         exit;
    }
}

?>

---

许多错误-例如：在“email2”之后忘记关闭标记。style.borderColor='red'；和是不推荐使用的HTML标记。此ifisset$\u GET['sent']{与POST值不匹配。

if(empty($_POST['name']) { 
    exit(/* simplified for clarity */);
}

<?php

if(isset($_POST['sent'])) {

    $nml = strlen($_POST['name']);
    $eml = strlen($_POST['email']);
    $msgl = strlen($_POST['msg']);

    if(empty($nml)) { 
        echo "<script>document.getElementById('name2').style.borderColor='red'; </script><center><font color='red'>Name* fields is required</font></center><br>";
    }
    if(empty($eml)) {
        echo "<script>document.getElementById('email2').style.borderColor='red';</script><center><font color='red'>Email* fields is required</font></center><br>";
    }
    if(empty($msgl)) {   
        echo "<script>document.getElementById('msg2').style.borderColor='red'; <center><font color='red'>Message* field is required</font></center><br>";    
    }

    if(empty($nml) || empty($eml) || empty($msgl)) {
         exit;
    }
}

?>