Javascript html array not saving and displaying
<p>For some reason this code is not saving the input into the array. I am also not able to display the array using a loop, but Im sure that is related to not being able to store the elements in to the array. How can I fix this?</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>var full_name;
    var dob;
    var gender;
    var nameList = new Array();
    var dateList = new Array();
    var genderList = new Array();
    var listLength = nameList.length;

    function displayMembers(nameList, dateList, genderList, listLength)
    {
        var str = " ";
        for(var i = 0;i &lt; listLength; i++) {
                document.write(nameList);
                document.write(dateList);
                document.write(genderList);
        }
    }
    function saveMember(nameList, dateList, genderList)
    {
        nameList[0]=data.push(document.getElementByName("full_name").value);
        dateList[0]=data.push(document.getElementByName("dob").value);
        genderList[0]=data.push(document.getElementByName("gender").value);
    }
    function clearList()
    {
        nameList= [];
        dateList= [];
        genderList= [];
    }</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;html&gt;
&lt;head&gt;
&lt;title&gt; INTERNET TECHNOLOGIES CLUB MEMBER LIST &lt;/title&gt;
&lt;/head&gt;
&lt;body&gt;
    &lt;form name="memberForm"&gt;
        &lt;h1&gt;
        INTERNET TECHNOLOGIES CLUB MEMBER LIST
        &lt;/h1&gt; Full name:
        &lt;input type="text" name="full_name" value="" /&gt; Date of Birth:
        &lt;input type="text" name="dob" value="" /&gt;
        &lt;br&gt;
        &lt;br&gt; Gender:
        &lt;input type="text" name="gender" value="" /&gt;
        &lt;br&gt;
        &lt;br&gt;
        &lt;textarea name="textBox" rows="10" cols="70"&gt;
            Full Name Date of Birth Gender
        &lt;/textarea&gt;
        &lt;br&gt;
        &lt;input type="button" value="NEXT" onclick="saveMember()" /&gt;
        &lt;input type="button" value="DISPLAY" onclick="displayMembers()" /&gt;
        &lt;input type="button" value="CLEAR" onclick="clearList()" /&gt;
    &lt;/form&gt;
&lt;/body&gt;
&lt;/html&gt;</code></pre>
</div>
</div>
</p>