SharePoint Add javascript in Allitems.aspx

Open Allitems.aspx

Search for : PlaceHolderMain

After : <asp:Content ContentPlaceHolderId="PlaceHolderMain" runat="server"> tag add javascript

Looks like this...

<asp:Content ContentPlaceHolderId="PlaceHolderMain" runat="server">
<script type="text/javascript" src="/jquery-1.9.1.js"></script>
​<script type="text/javascript">

$( document ).ready(function() {
alert('kk');
});