Asp. Net upload image Verification Code

1. client-side Verification

1. <Script language = "javascript">
2. Img = new Image ();
3. Function Check_FileTypeAndFileSize ()
4. {
5. // Obtain the upload path
6. Var str = document. all. uploadFile. value;
8. // Verify that the upload path is not empty
9. If (str = "")
10. {
11. Alert ("select the image to upload first! ");
12. Return false;
13. }
14. // Verify that the format of the uploaded file is correct
15. Var pos = str. lastIndexOf (".");
16. Var lastname = str. substring (pos, str. length)
17. If (lastname. toLowerCase ()! = ". Jpg" & lastname. toLowerCase ()! = ". Gif ")
18. {
19. Alert ("the file type you uploaded is" lastname ", and the image must be JPG or GIF ");
20. Return false;
21. }
22. // Verify the width and height of the uploaded file
23. If (img. width/img. height & gt; 1.6)
24. {
25. Return confirm (the image you uploaded is larger than. Are you sure you want to upload it ?);
26. }
28. // Verify whether the size of the uploaded file has exceeded
29. If (img. fileSize/1024> 150)
30. {
31. Alert ("the size of the file you uploaded exceeds the limit of KB! ");
32. Return false;
33. }
34. Return true;
35. }
37. // Upload the file box address change event to preview the image instantly
38. Function changephoto ()
39. {
40. Img. src = document. all. uploadFile. value;
42. }
43. // -->
44. </Script>
46. <Div>
47. <Upload: InputFile ID = "uploadFile" name = "UploadFilePath" runat = "server" onchange = "changephoto ()"/>
48. <Asp: Button ID = "btnUpload" runat = "server" Text = "Upload" OnClientClick = "return Check_FileTypeAndFileSize ()"
50. OnClick = "btnUpload_Click"/>
51. </Div>
52. <Div class = "upload">
54. </Div>