Pure JavaScript Send POST Data Without a Form
Is there a way to send data using the POST method without a form and without refreshing the page using only pure JavaScript (not jQuery $.post())? Maybe httprequest or something else (just can't find it now)?
Solution 1:
You can send it and insert the data to the body:
var xhr = new XMLHttpRequest();
xhr.open("POST", yourUrl, true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify({
value: value
}));
By the way, for get request:
var xhr = new XMLHttpRequest();
// we defined the xhr
xhr.onreadystatechange = function () {
if (this.readyState != 4) return;
if (this.status == 200) {
var data = JSON.parse(this.responseText);
// we get the returned data
}
// end of state change: it can be after some time (async)
};
xhr.open('GET', yourUrl, true);
xhr.send();
Solution 2:
The Fetch API is intended to make GET requests easy, but it is able to POST as well.
let data = {element: "barium"};
fetch("/post/data/here", {
method: "POST",
headers: {'Content-Type': 'application/json'},
body: JSON.stringify(data)
}).then(res => {
console.log("Request complete! response:", res);
});
If you are as lazy as me (or just prefer a shortcut/helper):
window.post = function(url, data) {
return fetch(url, {method: "POST", headers: {'Content-Type': 'application/json'}, body: JSON.stringify(data)});
}
// ...
post("post/data/here", {element: "osmium"});
Solution 3:
You can use the XMLHttpRequest object as follows:
xhr.open("POST", url, true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
xhr.send(someStuff);
That code would post someStuff to url. Just make sure that when you create your XMLHttpRequest object, it will be cross-browser compatible. There are endless examples out there of how to do that.
Solution 4:
Also, RESTful lets you get data back from a POST request.
JS (put in static/hello.html to serve via Python):
<html><head><meta charset="utf-8"/></head><body>
Hello.
<script>
var xhr = new XMLHttpRequest();
xhr.open("POST", "/postman", true);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify({
value: 'value'
}));
xhr.onload = function() {
console.log("HELLO")
console.log(this.responseText);
var data = JSON.parse(this.responseText);
console.log(data);
}
</script></body></html>
Python server (for testing):
import time, threading, socket, SocketServer, BaseHTTPServer
import os, traceback, sys, json
log_lock = threading.Lock()
log_next_thread_id = 0
# Local log functiondef
def Log(module, msg):
with log_lock:
thread = threading.current_thread().__name__
msg = "%s %s: %s" % (module, thread, msg)
sys.stderr.write(msg + '\n')
def Log_Traceback():
t = traceback.format_exc().strip('\n').split('\n')
if ', in ' in t[-3]:
t[-3] = t[-3].replace(', in','\n***\n*** In') + '(...):'
t[-2] += '\n***'
err = '\n*** '.join(t[-3:]).replace('"','').replace(' File ', '')
err = err.replace(', line',':')
Log("Traceback", '\n'.join(t[:-3]) + '\n\n\n***\n*** ' + err + '\n***\n\n')
os._exit(4)
def Set_Thread_Label(s):
global log_next_thread_id
with log_lock:
threading.current_thread().__name__ = "%d%s" \
% (log_next_thread_id, s)
log_next_thread_id += 1
class Handler(BaseHTTPServer.BaseHTTPRequestHandler):
def do_GET(self):
Set_Thread_Label(self.path + "[get]")
try:
Log("HTTP", "PATH='%s'" % self.path)
with open('static' + self.path) as f:
data = f.read()
Log("Static", "DATA='%s'" % data)
self.send_response(200)
self.send_header("Content-type", "text/html")
self.end_headers()
self.wfile.write(data)
except:
Log_Traceback()
def do_POST(self):
Set_Thread_Label(self.path + "[post]")
try:
length = int(self.headers.getheader('content-length'))
req = self.rfile.read(length)
Log("HTTP", "PATH='%s'" % self.path)
Log("URL", "request data = %s" % req)
req = json.loads(req)
response = {'req': req}
response = json.dumps(response)
Log("URL", "response data = %s" % response)
self.send_response(200)
self.send_header("Content-type", "application/json")
self.send_header("content-length", str(len(response)))
self.end_headers()
self.wfile.write(response)
except:
Log_Traceback()
# Create ONE socket.
addr = ('', 8000)
sock = socket.socket (socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(addr)
sock.listen(5)
# Launch 100 listener threads.
class Thread(threading.Thread):
def __init__(self, i):
threading.Thread.__init__(self)
self.i = i
self.daemon = True
self.start()
def run(self):
httpd = BaseHTTPServer.HTTPServer(addr, Handler, False)
# Prevent the HTTP server from re-binding every handler.
# https://stackoverflow.com/questions/46210672/
httpd.socket = sock
httpd.server_bind = self.server_close = lambda self: None
httpd.serve_forever()
[Thread(i) for i in range(10)]
time.sleep(9e9)
Console log (chrome):
HELLO
hello.html:14 {"req": {"value": "value"}}
hello.html:16
{req: {…}}
req
:
{value: "value"}
__proto__
:
Object
Console log (firefox):
GET
http://XXXXX:8000/hello.html [HTTP/1.0 200 OK 0ms]
POST
XHR
http://XXXXX:8000/postman [HTTP/1.0 200 OK 0ms]
HELLO hello.html:13:3
{"req": {"value": "value"}} hello.html:14:3
Object { req: Object }
Console log (Edge):
HTML1300: Navigation occurred.
hello.html
HTML1527: DOCTYPE expected. Consider adding a valid HTML5 doctype: "<!DOCTYPE html>".
hello.html (1,1)
Current window: XXXXX/hello.html
HELLO
hello.html (13,3)
{"req": {"value": "value"}}
hello.html (14,3)
[object Object]
hello.html (16,3)
{
[functions]: ,
__proto__: { },
req: {
[functions]: ,
__proto__: { },
value: "value"
}
}
Python log:
HTTP 8/postman[post]: PATH='/postman'
URL 8/postman[post]: request data = {"value":"value"}
URL 8/postman[post]: response data = {"req": {"value": "value"}}