Please check this code
function DisableTextBox() {
var buttonList = document.getElementById('<%=chkBoxList.ClientID %>');
var inputs = buttonList.getElementsByTagName("input");
var txtBox1 = document.getElementById('<%=txtBOX1.ClientID %>');
var txtBox2 = document.getElementById('<%=txtBOX2.ClientID %>');
var txtBox3 = document.getElementById('<%=txtBOX3.ClientID %>');
if (inputs[0].checked) {
txtBox1.disabled = true;
txtBox2.disabled = true;
txtBox3.disabled = true;
}
else {
txtBox1.disabled = false;
txtBox2.disabled = false;
txtBox3.disabled = false;
}
}
<asp:radiobuttonlist id="chkBoxList" runat="server" onclick="DisableTextBox(this);" xmlns:asp="#unknown">
<asp:listitem text="Cash" value="0" />
<asp:listitem text="Check" value="1" />
<asp:listitem text="Draft" value="2" />
</asp:radiobuttonlist>
<asp:textbox id="txtBOX1" runat="server" xmlns:asp="#unknown" />
<asp:textbox id="txtBOX2" runat="server" xmlns:asp="#unknown" />
<asp:textbox id="txtBOX3" runat="server" xmlns:asp="#unknown" />
you can attempt with Jquey too and line of code will be decreased Thanks.