Question

我是php的新手，所以我坚持这个基本问题。在这里，我创建了一个文本框和一个提交按钮。我想要的是，当我输入单词＆＃34; red＆＃34;在文本框中，它的背景将自动变为红色，但不幸的是问题是它没有产生任何影响。任何帮助都非常感谢。谢谢。

<html>
<head>
<title>

practice

</title>
<style type="text/css">
.red
{
background-color: red;
}
.blue
{
background-color: blue;
}
.yellow
{
background-color: yellow;
}
</style>
</head>
<body>
<?php
$fval = $_POST["val"];
    if( isset( $_POST["colorme"] ) ) {
    if($fval == "red")
    {
    echo S_POST['val'] = "red";
    }
    elseif($fval == "blue")
    {
    echo  S_POST['val'] = "blue";
    }
    elseif($fval == "yellow")
    {
    echo S_POST['val'] = "yellow";
    }
    }

?>
<form method="post">
<input type="text" name="val"  class="<?php echo $_POST['val'] ?>">

<input type="submit" name="colorme">
</form>

</body>
</html>

Answer 1

你的例子

<html>
  <head>
    <title>practice</title>
    <style type="text/css">
     .red{background-color: red;}
     .blue{background-color: blue;}
     .yellow{background-color: yellow;}
    </style>
   </head>
<body>
 <?php
    $fval = isset($_POST["val"])?trim($_POST["val"]):'';   
 ?>
 <form method="post">
  <input type="text" name="val"  class="<?php echo $fval ?>">
  <input type="submit" name="colormoko">
 </form>

 </body>
 </html>

Answer 2

为我尝试这个工作

<html>
    <head>
        <title>

        practice

    </title>
    <style type="text/css">
        .red
        {
            background-color: red;
        }
        .blue
        {
            background-color: blue;
        }
        .yellow
        {
            background-color: yellow;
        }
    </style>
</head>
<body>
<?php
$fval = "";
if( isset( $_POST["colormoko"] ) ) {
    $fval = $_POST['val'];
    if($fval == "red")
    {
        echo "<red>";
    }
    elseif($fval == "blue")
    {
        echo"<blue>";
    }
    elseif($fval == "yellow")
    {
        echo"<yellow>";
    }
}

?>
<form method="post">
    <input type="text" name="val"  class="<?php echo $fval ?>">

    <input type="submit" name="colormoko">
</form>

</body>
</html>

enter image description here

Answer 3

function changeColor() {
  var textBox = document.getElementById("textbox_coloring");
  var color = textBox.value;
  textBox.style.backgroundColor = color;
}

<!DOCTYPE html>
<html>
  <head>
    <title> coloring textbox </title>
    <meta charset = 'utf-8' />
  </head>
  <body>
    <form>
      <input type = 'text' id = 'textbox_coloring' onkeyup='changeColor();'/>
    </form>
  </body>
</html>

此代码段通过插入文本值来更改textBox的样式来更改textBox的颜色。它使用“onkeyup”javascript属性，允许在按下某个键后访问textBox。

基本的PHP输入输出

3 个答案: