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Small JavaScript instance (judge whether the user inputs a number, intercept two digits, rounding)

Source: Internet
Author: User
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Reference post: http://topic.csdn.net/t/20060907/19/5006672.html

090103 check whether it is a number and greater than zero

  1. <% @ Page Language = "C #" autoeventwireup = "true" codefile = "default. aspx. cs" inherits = "test_default" %>
  3. <! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  5. <HTML xmlns = "http://www.w3.org/1999/xhtml">
  6. <Head runat = "server">
  7. <Title> check whether the number is greater than zero </title>
  8. <SCRIPT type = "text/JavaScript">
  9. // Judge the function.
  10. Function fchecknumbyid (ID ){
  11. VaR TXT = Document. getelementbyid (ID );
  12. If (! Isnan (txt. Value) & TXT. value> 0) // if it is a number, false is returned. If it is equal to zero, it cannot pass.
  13. Return true;
  14. Else
  15. {
  16. Return false;
  17. }
  18. }
  19. // Call judgment.
  20. Function fcheck (){
  21. If (fchecknumbyid ('tb1 '))
  22. {
  23. // Execute the business
  24. Alert ('verified ');
  25. Return true;
  26. }
  27. Else
  28. {
  29. Alert ('non-digit or less than 0! ');
  30. Return false;
  31. }
  32. }
  33. </SCRIPT>
  34. </Head>
  35. <Body>
  36. <Form ID = "form1" runat = "server">
  37. <Div>
  38. <Asp: textbox id = "tb1" runat = "server"> </ASP: textbox>
  39. <Input type = "button" onclick = "fcheck ();" value = "check"/>
  40. </Div>
  41. </Form>
  42. </Body>
  43. </Html>

Front-end

  1. <% @ Page Language = "C #" autoeventwireup = "true" codefile = "test1.aspx. cs" inherits = "xcgl_test1" %>
  3. <! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  4. <HTML xmlns = "http://www.w3.org/1999/xhtml">
  5. <Head runat = "server">
  6. <Title> call the client code to determine whether the input is qualified </title>
  8. <SCRIPT type = "text/JavaScript">
  9. Function fcheck (){
  10. VaR TXT = Document. getelementbyid ('tbenter ');
  11. If (txt. value = '')
  12. {
  13. Alert ('cannot be blank! ');
  14. Return false;
  15. }
  16. Else
  17. {
  18. If (isnan (txt. Value) // determines whether it is a non-digit
  19. {
  20. Alert ('cannot be a non-digit! ');
  21. Return false;
  22. }
  23. Else
  24. {
  25. Alert ('prompt, only two digits are retained in decimal multiples. ');
  26. Return true;
  27. }
  28. }
  29. }
  30. </SCRIPT>
  32. </Head>
  33. <Body>
  34. <Form ID = "form1" runat = "server">
  35. <Div>
  36. <Asp: textbox id = "tbenter" runat = "server"> </ASP: textbox>
  37. <Asp: button id = "btncheck" runat = "server" text = "the server code is executed only after the client determines that the server code is successful." onclick = "btncheck_click"
  38. Onclientclick = "Return fcheck ();"/>
  39. </Div>
  40. </Form>
  41. </Body>
  42. </Html>

Background

  1. Using system;
  2. Using system. Data;
  3. Using system. configuration;
  4. Using system. collections;
  5. Using system. Web;
  6. Using system. Web. Security;
  7. Using system. Web. UI;
  8. Using system. Web. UI. webcontrols;
  9. Using system. Web. UI. webcontrols. webparts;
  10. Using system. Web. UI. htmlcontrols;
  12. Public partial class xcgl_test1: system. Web. UI. Page
  13. {
  14. Protected void page_load (Object sender, eventargs E)
  15. {
  17. }
  18. Protected void btncheck_click (Object sender, eventargs E)
  19. {
  20. // Take two decimal places without rounding.
  21. Double D = convert. todouble (tbenter. Text. Trim ());
  22. Double I = (double) (INT) (D x 100)/100;
  23. // Rounding
  24. String STR = D. tostring ("0 .##");
  26. Response. Write (I + "|" + Str );
  27. }
  28. }

End

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