Introduction

In this article, I explain how to create validations for a Text Box control in ASP.Net. I will start with the following three validations:

  1. Accept alphanumeric characters
  2. Accept Alphabet characters
  3. Accept numeric characters

Requirement

Add the following line in the head section:

  1. <script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.js"></script>

Code

First write the following script in your page to accept alphanumeric characters :

  1. <script type="text/javascript">
  2. $(function () {
  3. $('#txtalphaNumeric').keydown(function (e) {
  4. if (e.shiftKey || e.ctrlKey || e.altKey) {
  5. e.preventDefault();
  6. } else {
  7. var key = e.keyCode;
  8. if (!((key == 8) || (key == 32) || (key == 46) || (key >= 35 && key <= 40) || (key >= 65 && key <= 90) || (key >= 48 && key <= 57) || (key >= 96 && key <= 105))) {
  9. e.preventDefault();
  10. }
  11. }
  12. });
  13. });

When you have done that code, add a TextBox and provide "txtalphaNumeric" for the id of the TextBox like :

  1. <asp:TextBox ID="txtalphaNumeric" runat="server"></asp:TextBox>

2. Accept Alphabet characters

First write the following script in your page :

  1. $(function () {
  2. $('#txtalphabet').keydown(function (e) {
  3. if (e.shiftKey || e.ctrlKey || e.altKey) {
  4. e.preventDefault();
  5. } else {
  6. var key = e.keyCode;
  7. if (!((key == 8) || (key == 32) || (key == 46) || (key >= 35 && key <= 40) || (key >= 65 && key <= 90))) {
  8. e.preventDefault();
  9. }
  10. }
  11. });
  12. });

When you have done that code, add a TextBox and provide "txtalphabet" for the id of the TextBox like:

  1. <asp:TextBox ID="txtalphabet" runat="server"></asp:TextBox>

3. Accept numeric characters

First write the following script in your page :

  1. $(function () {
  2. $('#txtNumeric').keydown(function (e) {
  3. if (e.shiftKey || e.ctrlKey || e.altKey) {
  4. e.preventDefault();
  5. } else {
  6. var key = e.keyCode;
  7. if (!((key == 8) || (key == 46) || (key >= 35 && key <= 40) || (key >= 48 && key <= 57) || (key >= 96 && key <= 105))) {
  8. e.preventDefault();
  9. }
  10. }
  11. });
  12. });

After you have done that code, add a TextBox and provide "txtalphabet" for the id of the TextBox like:

  1. <asp:TextBox ID="txtNumeric" runat="server"></asp:TextBox>

Complete code

  1. <html xmlns="http://www.w3.org/1999/xhtml">
  2. <head>
  3. <title>jQuery Allow only alphanumeric characters in TextBox</title>
  4. <script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.js"></script>
  5. <script type="text/javascript">
  6. $(function () {
  7. $('#txtalphaNumeric').keydown(function (e) {
  8. if (e.shiftKey || e.ctrlKey || e.altKey) {
  9. e.preventDefault();
  10. } else {
  11. var key = e.keyCode;
  12. if (!((key == 8) || (key == 32) || (key == 46) || (key >= 35 && key <= 40) || (key >= 65 && key <= 90) || (key >= 48 && key <= 57) || (key >= 96 && key <= 105))) {
  13. e.preventDefault();
  14. }
  15. }
  16. });
  17. });
  19. //only alphabet
  21. $(function () {
  22. $('#txtalphabet').keydown(function (e) {
  23. if (e.shiftKey || e.ctrlKey || e.altKey) {
  24. e.preventDefault();
  25. } else {
  26. var key = e.keyCode;
  27. if (!((key == 8) || (key == 32) || (key == 46) || (key >= 35 && key <= 40) || (key >= 65 && key <= 90))) {
  28. e.preventDefault();
  29. }
  30. }
  31. });
  32. });
  34. //Only Numeric
  36. $(function () {
  37. $('#txtNumeric').keydown(function (e) {
  38. if (e.shiftKey || e.ctrlKey || e.altKey) {
  39. e.preventDefault();
  40. } else {
  41. var key = e.keyCode;
  42. if (!((key == 8) || (key == 46) || (key >= 35 && key <= 40) || (key >= 48 && key <= 57) || (key >= 96 && key <= 105))) {
  43. e.preventDefault();
  44. }
  45. }
  46. });
  47. });
  48. </script>
  49. </head>
  50. <body>
  51. <form id="form1" runat="server">
  52. <div>
  53. <b>Enter Text:</b><asp:TextBox ID="txtalphaNumeric" runat="server"></asp:TextBox>Accept alphanumeric characters<b><br />
  54. Enter Text:</b><asp:TextBox ID="txtalphabet" runat="server"></asp:TextBox>
  55. Accept only Alphabets characters
  56. Enter text :<asp:TextBox ID="txtNumeric" runat="server"></asp:TextBox>Accept only Numeric values\
  57. </div>
  58. </form>
  59. </body>
  60. </html>