input[type='text']
{
background-image:url('Images/search.gif');
background-repeat:no-repeat;
padding-left:20px;
}
<asp:TextBox ID="txt1" runat="server"></asp:TextBox>
<asp:TextBox ID="txt2" runat="server"></asp:TextBox>
<asp:TextBox ID="txt3" runat="server"></asp:TextBox>
<asp:TextBox ID="txt4" runat="server"></asp:TextBox>
<input type="text" />
For a particular text box .searchBox_1
{
background-image:url('Images/search.gif');
background-repeat:no-repeat;
padding-left:20px;
}
<asp:TextBox ID="txt" runat="server" CssClass="searchBox_1"></asp:TextBox>