CODEWITHSUNDEEP
javascriptpythonxmlhttprequest
repzero
repzero

Reputation: 8412

send data to a python cgi script for processing from browser using pure javascript

I have an html test file with the following

<!doctype html>
<html lang="en">
    <meta charset="utf-8">
    <body>
        <script type="text/javascript">
        var httprequest=new XMLHttpRequest();
        httprequest.open("POST","hello.cgi",true);
        httprequest.onload=function(){
        if(httprequest.status==200){
            alert("");
         }// end of if
         }//end of onload
         var content={"hello":"world"};
         httprequest.send(JSON.stringify(content));
         alert(httprequest.responseText)
          </script
    </body>
</html>
</doctype>

In this scenario I am trying to send the data {"hello":"world"}; to a python cgi script

This is my python script that works well with data submitted from a <form> html tag

#!/usr/bin/python
try:
    import sys
    import cgi
    import traceback
    print("Content-type: text/html\n\n")
    print "<h1>YES</h1>"
    formData = cgi.FieldStorage()
    print(formData)
    print(s)
except Exception as e:
    print(e.message)
    print(traceback.print_exc())

When I send the data {"hello":"world"}, my browser alert box shows no data returned from the cgi script.

As reflected in the cgi script, I am trying to print "YES" and print the data that was sent from javascript.

I have found several questions relating to use of $.ajax to do this but haven't come across a method using XMLHttpRequest()

Question

How can I send data to a python cgi script for processing from my browser using pure javascript (no jquery)

Upvotes: 1

Views: 904

Answers (1)

Pointy
Pointy

Reputation: 413702

The HTTP request you're performing happens on its own time. The call to httprequest.send() starts the operation, but that function call returns almost immediately, and definitely before the remote server has responded. This asynchronous behavior is a basic fact of life in JavaScript environments.

The whole reason for the "onload" callback is to make it possible for you to write code that happens when the HTTP request actually completes. The browser will invoke that function with the results when the results become available. That might be in 100 milliseconds, or 10 seconds; it all depends on the server and the network.

Upvotes: 1

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