AJAX DB Instance

AJAX is used to create more dynamic applications.

AJAX ASP Instances

The following example shows how a Web page communicates with the server when the user types a character in the input box:

Instance

Please type the letter (A-Z) in the following input box:

Suggestions:

Try the source code yourself

Example explanation-HTML page

The "Showhint ()" function is executed when the user types a character in the input box above. This function is triggered by the "onkeyup" event:

<! DOCTYPE html>
Source Code Explanation:
If the input box is empty (str.length==0), the function empties the contents of the placeholder txthint and launches the function.
If the input box is not empty, then Showhint () performs the following steps:

 
 

  
  
 
   
Create a XMLHttpRequest Object
 
   
Create a function that executes when the server responds ready
 
   
Send a request to a file on the server
 
   
Note the parameter (q) added to the end of the URL (contains the contents of the input box)
 
  
 
 
ASP file
The server page of the above JavaScript call is an ASP file named "Gethint.asp".
The source code in "gethint.asp" checks the name array and returns the corresponding name to the browser:
<%response.expires=-1dim A (+) ' Fill up array with Namesa (1) = "Anna" A (2) = "Brittany" A (3) = "Cinderella" A (4) = "Diana" A ( 5) = "Eva" A (6) = "Fiona" A (7) = "Gunda" A (8) = "Hege" A (9) = "Inga" A (Ten) = "Johanna" A (one) = "Kitty" A (a) = "Linda" A (All) = "Nina" A ( = "Ophelia" A () = "Petunia" A (+) = "Amanda" A (+) = "Raquel" a () = "Cindy" A (+) = "Doris" a () = "Eve" A (+) = "Evita" A (22 ) = "Sunniva" A (All) = "Tove" a () = "Unni" A (+) = "Violet" A (+) = "Liza" a () = "Elizabeth" a () = "Ellen" a () = "A", "Wenche" A (30) = "Vicky" ' gets parameter qq=ucase from URL (Request.QueryString ("Q")) ' If the length q>0, then find all hints from the array if Len (q) >0 then  hint= ""  For I=1 to +    if Q=ucase (Mid (A (i), 1,len (q))) then      if hint= "and then        hint=a (i)      else        Hint=hint &", "& A (i)      End If    end  if NextEnd if no prompt is found, output" no suggestion "' or output the correct valuesif hint=" "then< C10/>response.write ("no suggestion") Else  Response.Write (hint) end if%>
Source Code Explanation:
If JavaScript sends any text (that is, strlen ($q) is greater than 0), it occurs:

 
 

  
  
 
   
Find names that match characters from JavaScript
 
   
If no match is found, the response string is set to "no suggestion"
 
   
If one or more matching names are found, the response string is set with all names
 
   
Send the response to the placeholder "Txthint"
 
  
 
 
Http://www.w3school.com.cn/asp/asp_ajax_asp.asp
AJAX DB Instance