Access to XMLHttpRequest has been blocked by CORS policy code example
Example 1: javascript access to xmlhttprequest at from origin 'null' has been blocked by cors policy
Example 2: Access to XMLHttpRequest has been blocked by CORS policy
const cors = require('cors');
const corsOptions ={
origin:'http://localhost:3000',
credentials:true,
optionSuccessStatus:200
}
app.use(cors(corsOptions));
Example 3: Access to XMLHttpRequest at 'http://localhost/MySQL_pracs/InsertUser.php' from origin 'http://localhost:4200' has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.
<?php
header('Access-Control-Allow-Headers: Content-Type');
-----
?>
Example 4: ccess to XMLHttpRequest at 'http://127.0.0.1:5000/ has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
@app.route('your route', methods=['GET'])
def yourMethod(params):
response = flask.jsonify({'some': 'data'})
response.headers.add('Access-Control-Allow-Origin', '*')
return response
Example 5: Access to XMLHttpRequest at from origin HTTP localhost:3000 has been blocked by CORS policy
const cors = require('cors');
const corsOptions ={
origin:'http://localhost:3000',
credentials:true,
optionSuccessStatus:200
}
app.use(cors(corsOptions));