. Net does not refresh the new page to refresh the verification code js Implementation Method

In fact, a lot of friends say that ajax is actually not the case. We only need to use js to implement the verification code refresh and replacement function instead of refreshing the page. If you need it, you can refer to it.

The purpose of refreshing the verification code using Javascript is to re-obtain the verification code without refreshing the page.

JS Code:

The Code is as follows:	Copy code
Function RefreshCode (obj ){ Obj. src = obj. src + "? Code = "+ Math. random (); }

 

Call:

The Code is as follows:	Copy code
Onclick = "RefreshCode (this)"/>

 

Lower instance (1)

Html page

The Code is as follows:

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<Script> Function fGetCode () { Document. getElementById ("getcode"). src = "asp.net. aspx? "+ Math. random (); } </Script> <Label> Verification Code </label> <Asp: TextBox ID = "txt_checkCode" runat = "server" Width = "178px"> </asp: TextBox> < Href = "javascript: fGetCode ()"> change the Verification Code </a> Asp.net. aspx Using System; Using System. Collections. Generic; Using System. Linq; Using System. Web; Using System. Web. UI; Using System. Web. UI. WebControls; Using System. Drawing; Namespace online student Examination System { Public partial class AjaxAutoCode: System. Web. UI. Page { // Verify the number Public string authcode = string. Empty; Protected void Page_Load (object sender, EventArgs e) { # Region the first method to generate a verification code Random random = new Random (); Authcode = random. Next (1111,999 9). ToString (); // Construct an image Bitmap image = new Bitmap (authcode. Length * 12, 25 ); // Create a canvas Graphics g = Graphics. FromImage (image ); Try { G. Clear (Color. White ); For (int I = 0; I <25; I ++) { Int x1 = random. Next (image. Width ); Int x2 = random. Next (image. Width ); Int y1 = random. Next (image. Height ); Int y2 = random. Next (image. Height ); // Link two-point lines G. DrawLine (new Pen (Color. Silver), x1, y1, x2, y2 ); } Font font = new Font ("Arial", 12, FontStyle. Bold | FontStyle. Italic ); System. Drawing. Drawing2D. LinearGradientBrush brush = new System. Drawing. Drawing2D. LinearGradientBrush ( New Rectangle (0, 0, image. Width, image. Height), Color. Blue, Color. DarkBlue, 1.2f, True ); G. DrawString (authcode, font, brush, 2, 2 ); // Foreground Noise For (int I = 0; I <100; I ++) { Int x = random. Next (image. Width ); Int y = random. Next (image. Height ); Image. SetPixel (x, y, Color. FromArgb (random. Next ())); } G. DrawRectangle (new Pen (Color. Silver), 0, 0, image. Width-1, image. Height-1 ); System. IO. MemoryStream MS = new System. IO. MemoryStream (); Image. Save (MS, System. Drawing. Imaging. ImageFormat. Gif ); Ms. WriteTo (this. Response. OutputStream ); Ms. Close (); This. Response. ContentType = "image/gif "; } Finally { Image. Dispose (); G. Dispose (); } # Endregion } } }