I use a kind of javascript,when i use it in a page without master page it works properly but when i use it in content page that use master page it doesn't work what should i do for this problem?i don't use any code in masterpage for javascript is it necesssary ?\[code\]//Page1 without MasterPage....<head runat="server"> <link rel="stylesheet" href="http://stackoverflow.com/questions/12789431/StyleSheet.css" type="text/css" media="screen"/> <script src="http://stackoverflow.com/questions/12789431/jquery-1.4.4.min.js" type="text/javascript" charset="utf-8"></script> <script src="http://stackoverflow.com/questions/12789431/jquery.maskedinput.js" type="text/javascript"></script> <script type="text/javascript"> $(function () { $.mask.definitions['~'] = "[+-]"; $("#date").mask("99/99/9999"); //Date $("input").blur(function () { $("#info").html("Unmasked value: " + $(this).mask()); }).dblclick(function () { $(this).unmask(); }); }); </script></head>....<body> <form id="form1" runat="server"> date : <asp:TextBox ID="date" runat="server" ></asp:TextBox>.....//page2 with MasterPage...<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> <link rel="stylesheet" href="http://stackoverflow.com/questions/12789431/StyleSheet.css" type="text/css" media="screen"/> <script src="http://stackoverflow.com/questions/12789431/jquery.maskedinput.js" type="text/javascript" charset="utf-8"></script> <script src="http://stackoverflow.com/questions/12789431/jquery-1.4.4.min.js" type="text/javascript"></script> <script type="text/javascript"> $(function () { $.mask.definitions['~'] = "[+-]"; $("#date").mask("99/99/9999"); //Date $("input").blur(function () { $("#info").html("Unmasked value: " + $(this).mask()); }).dblclick(function () { $(this).unmask(); }); }); </script></asp:Content>....<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"> date : <asp:TextBox ID="date" runat="server" ></asp:TextBox></asp:Content>//Master Page...<head runat="server"> <asp:ContentPlaceHolder id="head" runat="server"> </asp:ContentPlaceHolder></head><body> <form id="form1" runat="server"> <div> <asp:ContentPlaceHolder id="ContentPlaceHolder1" runat="server"> </asp:ContentPlaceHolder> </div> </form></body></html>\[/code\]