title: Don't have the page refresh after selectedindexchanged of dropdown list?
body: <p>I'm working with two dropdown boxes after a user selects the first required drop down based on what they choose the other drop down will load the final list. I have that working but I don't want the page to reload on once the first dropdown option is picked is there a way around this below is my test code</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>Behind code
  
  protected void Page_Load(object sender, EventArgs e)
          {
              if (!IsPostBack)
              {
                  DropDownList1.Items.Add(new ListItem("3 Days", "3 Days"));
                  DropDownList1.Items.Add(new ListItem("4 Days", "4 Days"));
                  DropDownList1.Items.Add(new ListItem("5 Days", "5 Days"));
                  DropDownList1.Items.Add(new ListItem("7 Days", "7 Days"));
              }
          }
  
          protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
          {
              DropDownList2.Items.Clear();
              DropDownList3.Items.AddRange(GetListItems(DropDownList1.SelectedValue));
          }
  
          private ListItem[] GetListItems(string value)
          {
              var items = new List
                  &lt;ListItem&gt;
                  ();
  
              if (value == "3 Days")
              {
                  DropDownList2.Items.Add(new ListItem("1", "1"));
              }
  
              if (value == "4 Days")
              {
                  DropDownList2.Items.Add(new ListItem("2", "2"));
              }
  
              if (value == "5 Days")
              {
                  DropDownList2.Items.Add(new ListItem("3", "3"));
              }
  
              if (value == "7 Days")
              {
                  DropDownList2.Items.Add(new ListItem("4", "4"));
              }
              return items.ToArray();
          }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="1"&gt;
  &lt;asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"&gt;
    &lt;asp:ListItem Text="Select..." Value="No selection made"&gt;&lt;/asp:ListItem&gt;
  &lt;/asp:DropDownList&gt;
  &lt;/div&gt;
  &lt;div class="1"&gt;
    &lt;asp:DropDownList ID="DropDownList2" runat="server"&gt;
      &lt;asp:ListItem Text="Select..." Value="No selection made"&gt;&lt;/asp:ListItem&gt;
    &lt;/asp:DropDownList&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>