Question

＆lt; form action =＆＃34;＆＃34;方法=＆＃34; POST＆＃34;＆GT; ＆lt; select name =＆＃39;选择＆＃39;＆gt; ＆LT;选项＆GT;芒果＆LT; /选项＆GT; ＆LT;选项＆GT;香蕉＆LT; /选项＆GT; ＆LT; /选择＆GT; ＆LT; /形式＆GT; 如果我有这个选项值，我怎么知道设置了哪个值而不是传递值。 if（已设置（$ _ POST [＆＃39;选择＆＃39;]））{ echo＆＃34; Something＆＃34 ;; } 上面是选择标签，它工作正常，但我尝试给芒果和香蕉的名称，但没有得到我选择的价值。有人请帮忙。谢谢！

Answer 1

选项需要一些值，例如：

<form action="" method="POST">
<select name='choose'>
<option value="mango" >mango</option>
<option value="banana">banana</option>
</select>
</form>

PHP：将更改设置为（）到isset()并添加if-else条件，以处理不同的输入

if( isset( $_POST['choose'] ) ){
    if( $_POST['choose'] === "mango" ) {
        echo "do the mango";
    } elseif( $_POST['choose'] === "banana" ) {
        echo "do the banana";
    } else {
        echo "nothing chosen";
    }
}

将其传递给varibale

$chosen_fruit = "none";

// You can also pass the value to a variable
if( isset( $_POST['choose'] ) ){
    if( $_POST['choose'] === "mango" ) {
        $chosen_fruit = "mango";
    } elseif( $_POST['choose'] === "banana" ) {
       $chosen_fruit = "banana";
    }
} 


// here you can use the value of the variable
echo $chosen_fruit;// echo outside the if condition

如果您想了解有关变量范围的更多信息，请查看here

Answer 2

您必须为每个选项设置值

<form action="" method="POST">
<select name='choose'>
<option value="mango" >mango</option>
<option value="banana">banana</option>
</select>
</form>

if(isset($_POST['choose'])){ //replace is set to isset
echo "Something";
}

Answer 3

更改为

 <option value="mango">mango</option>
 <option value="banana">banana</option>

isset中有空格，所以改变它：

 $data="";
 if(isset($_POST['choose'])){
   $value = $_POST['choose'];
   if($value=="fruitValue") {
    $data = "do_soemthing"; 
   }    
 }

$data访问数据变量。

检查从<select>标签中选择的选项值

3 个答案: