JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="city" />
<input type="button" value="submit" onclick="httpGet()" />
<div id="placeholder"></div>

JavaScript

// this function must be global since the script is executed in global scope
    function processResponse(obj1) {
        document.getElementById("placeholder").innerHTML =
            obj1.message + " " + obj1.list[0].name;
    }
     
    function httpGet() {
        var url = "http://api.openweathermap.org/data/2.5/find?q=chennai&units=metric&mode=json";
        // the following line is just to explictly show the `callback` parameter
        url += '&callback=processResponse';
        //  name of our function ^^^^^^^^
        
        var script = document.createElement('script');
        script.src = url;
        document.body.appendChild(script);
    }