Textarea锁定

Question

我有一个我设计的简单调查表，但由于某种原因，一行代码无效。

问题5.如果用户选择单选按钮YES，则他们必须在textarea中输入内容，否则不得发送表格。

如果不是，则应锁定textarea，以便无法输入任何内容。

以下是代码：感谢女士们和女士们的帮助

5. Are you using other non-franchise service centres? 
<br>
*if yes is there any other reason you would do so other than price
<br>
<input type="radio" name="question5"
<?php if (isset($question5) && $question5=="Yes") echo "checked";?>
value="Yes">Yes
<br>
<input type="radio" name="question5"
<?php if (isset($question5) && $question5=="No") echo "checked";?>
value="No">No
<br>
<textarea name="question5" rows="5" cols="40"><?php echo $question5 </textarea>

Answer 1

选项1：隐藏textarea

＆＃13;

＆＃13;

function check5(selectedType){
  if (selectedType == 'Yes'){
    document.getElementById('5textarea').style.display = 'block'; 
	
  } else{
    
    document.getElementById('5textarea').style.display = 'none';
  
  }
}

＆＃13;

5. Are you using other non-franchise service centres? 
<br>
*if yes is there any other reason you would do so other than price
<br>
<input type="radio" name="question5"  value="Yes" onclick="check5(this.value)"> Yes
<br>
<input type="radio" name="question5" value="No" onclick="check5(this.value)"> No
<br>

<textarea id="5textarea" name="question5" rows="5" cols="40" style="display:none"></textarea>

＆＃13;

＆＃13;

＆＃13;

选项2：启用/禁用textarea（ NOT TESTED ）：

5. Are you using other non-franchise service centres? 
<br>
*if yes is there any other reason you would do so other than price
<br>
<input type="radio" name="question5"  value="Yes" onclick="check5(this.value)"> Yes
<br>
<input type="radio" name="question5" value="No" onclick="check5(this.value)"> No
<br>
<textarea id="5textarea" name="question5" rows="5" cols="40" disabled="true"></textarea>

并将javascript更改为：

function check5(selectedType){
if (selectedType == 'Yes'){
  document.getElementById("5textarea").disabled = false;

} else{

  document.getElementById("5textarea").disabled = true;
}
}

Answer 2

你必须使用javascript，因为PHP只在服务器上运行，不在浏览器中！

在此代码中，如果不需要，则禁用textarea，如果＆＃34;是＆＃34;检查并且textarea没有包含足够的文本，提交表单时出现错误：

＆＃13;

＆＃13;

// Javascript:
function validate() {
    var radioYes = document.getElementById('radioYes');
    var textarea = document.getElementById('textarea');
    
    if (radioYes.checked && textarea.value.length < 10) {
        alert('Enter at least 10 characters!');
        textarea.focus();
        return false;
    }
}

function toggle(value) {
	document.getElementById('textarea').disabled = value;
}

＆＃13;

/* CSS: */
* {
    font-family: sans-serif;
    margin: 4px;
}

＆＃13;

<!-- HTML/PHP: -->
<form action="#">
    5. Are you using other non-franchise service centres?<br>
    *if yes is there any other reason you would do so other than price?<br>
    
    <input type="radio" name="question5" value="Yes" onchange="toggle(this.selected)" id="radioYes">Yes<br>
    <input type="radio" name="question5" value="No" onchange="toggle(!this.selected)">No<br>
    
    <textarea id="textarea" name="question5" rows="5" cols="40" disabled></textarea><br>

    <input type="submit" value="Send" onclick="return validate()" />
</form>

＆＃13;

＆＃13;

＆＃13;

JSFiddle