Example 1: javascript http request
function _GET_REQUEST(url, response) {
var xhttp;
if (window.XMLHttpRequest) {
xhttp = new XMLHttpRequest();
} else {
xhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
response(this.responseText);
}
};
xhttp.open("GET", url, true);
xhttp.send();
}
function _POST_REQUEST(url, params, response) {
var xhttp;
if (window.XMLHttpRequest) {
xhttp = new XMLHttpRequest();
} else {
xhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
response(this.responseText);
}
};
xhttp.open("POST", url, true);
xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttp.send(params);
}
_GET_REQUEST('http://url.com', (response) => {
console.log(response);
});
_POST_REQUEST('http://url.com', 'parameter=sometext', (response) => {
console.log(response);
});
Example 2: http request javascript
function httpGetAsync(url, callback) {
var xmlHttp = new XMLHttpRequest();
xmlHttp.onreadystatechange = function() {
if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
callback(xmlHttp.responseText);
}
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
Example 3: javascript progress of xml http request
<!DOCTYPE html>
<html>
<body>
<p id="demo">result</p>
<button type="button" onclick="get_post_ajax();">Change Content</button>
<script type="text/javascript">
function update_progress(e)
{
if (e.lengthComputable)
{
var percentage = Math.round((e.loaded/e.total)*100);
console.log("percent " + percentage + '%' );
}
else
{
console.log("Unable to compute progress information since the total size is unknown");
}
}
function transfer_complete(e){console.log("The transfer is complete.");}
function transfer_failed(e){console.log("An error occurred while transferring the file.");}
function transfer_canceled(e){console.log("The transfer has been canceled by the user.");}
function get_post_ajax()
{
var xhttp;
if (window.XMLHttpRequest){xhttp = new XMLHttpRequest();}
else{xhttp = new ActiveXObject("Microsoft.XMLHTTP");}
xhttp.onprogress = update_progress;
xhttp.addEventListener("load", transfer_complete, false);
xhttp.addEventListener("error", transfer_failed, false);
xhttp.addEventListener("abort", transfer_canceled, false);
xhttp.onreadystatechange = function()
{
if (xhttp.readyState == 4 && xhttp.status == 200)
{
document.getElementById("demo").innerHTML = xhttp.responseText;
}
};
xhttp.open("GET", "http://it-tu.com/ajax_test.php", true);
xhttp.send();
}
</script>
</body>
</html>
Example 4: http request and http response
HTTP request method is made up of four components:
Request Method ==> Get, Post, Put, Delete (these are
the common ones)
Request URL ==> the URL of the resource
Request Header ==> Accept-Language, AcceptEncoding, User-Agent, Host
Request Body ==> This is the data to be sent to the
HTTP RESPONSE
resource HTTP -RESPONSE- method is made up of three
components:
Response Status Code ==> 200, 301, 404, 500
(these are the most common ones)
Response Header Fields ==> Date, Server, LastModified, Content-Type
Response Body ==> This is the data that comes
back to the client from the server.