How to call existing REST api from a HTML form?
Typically When user would like to get data from the server. client need to send a request to the server and get a response. Usually programmer will bind a request function with an specific element and events.
In this case you need to bind a request function with form element. As you didn't mention which event you want to happen, so I couldn't tell exactly solution.
The following code is a simple code that call REST API when user type on a text input, and show the result below the input text
Note that replace "URL" with your API call.
<!DOCTYPE html><html><body> <form> Keyword:<br> <input type="text" name="keyword" onkeyup="callREST()"><br> </form> <div id="response"></div> <script> function callREST() { var xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function() { if (this.readyState == 4 && this.status == 200) { document.getElementById("response").innerHTML = this.responseText; } }; xhttp.open("GET", "URL", true); xhttp.send(); } </script></body></html>