JQuery返回元素爲null

Question

Ruby on Rails 3. 我有一個div id我試圖隱藏或顯示基於選中複選框的值。我的腳本現在無法通過ID獲取元素。它返回null。我嘗試了輸入ID和名稱。兩者都返回null。

下面是腳本：

$(document).ready(function() { 
$('#device').change(function(event){ 
var hardware = document.getElementById('#survey_hardware_'); 
if (($(hardware).find("input[value='IP Phones']:checked").length) || ($(hardware).find("input[value='IP PBX Systems']:checked").length)) 
{ 
    $('#phonepbx').css('display', 'inline'); 
} 
else 
{ 
    $('#phonepbx').css('display', 'none'); 
} 
}); 
}); 

這是渲染HTML問題：

<div class="row" id="device"> 
<ul>1. What IP hardware does your company frequently sell and/or install? (select all that apply)<br/> 
<li style="display:block;"><input id="survey_hardware_" name="survey[hardware][]" type="checkbox" value="IP Phones" /> IP Phones</li> 
<li style="display:block;"><input id="survey_hardware_" name="survey[hardware][]" type="checkbox" value="IP PBX Systems" /> IP PBX Systems </li> 
<li style="display:block;"><input id="survey_hardware_" name="survey[hardware][]" type="checkbox" value="IP Security/Surveillance Systems" /> IP Security/Surveillance Systems</li> 
<li style="display:block;"><input id="survey_hardware_" name="survey[hardware][]" type="checkbox" value="IP infrastructure (cabling, switches...etc.)" /> IP infrastructure (cabling, switches...etc.)</li> 
</ul> 
</div> 

摘要：

document.getElementById('#survey_hardware_'); 

返回null。我試過#survey [硬件] []和#survey [硬件] [0]，全部爲空。我如何獲得元素？謝謝（請不要恨我李造型:)

解決方案

function checkHardware() { 
if ($('#device input:checkbox:eq(0)').is(':checked') || $('#device input:checkbox:eq(1)').is(':checked')) 
{ 
    $('#phonepbx').css('display', 'block'); 
} 

等等

Answer 1

嘗試不以 '＃'：

document.getElementById('survey_hardware_'); 

或者直接使用jQuery：

$('#survey_hardware_') 

Answer 2

爲什麼你使用getElementById？你有jQuery的，所以用：

$("#survey_hardware_").find(

Answer 3

喜歡的東西：（注意新的和獨特的ID）

<li style="display:block;"><input id="phones" name="survey[hardware][]" type="checkbox" value="IP Phones" /> IP Phones</li> 
<li style="display:block;"><input id="pbx" name="survey[hardware][]" type="checkbox" value="IP PBX Systems" /> IP PBX Systems </li> 
<li style="display:block;"><input id="security" name="survey[hardware][]" type="checkbox" value="IP Security/Surveillance Systems" /> IP Security/Surveillance Systems</li> 
<li style="display:block;"><input id="infra" name="survey[hardware][]" type="checkbox" value="IP infrastructure (cabling, switches...etc.)" /> IP infrastructure (cabling, switches...etc.)</li> 

，然後直接使用jQuery：$('#new_id_here')如已經提出。