add value in text aers js code example

Example 1: assign value to textarea

<textarea class="article-input" id="article-input" type="text" rows="9" >{{article}}</textarea>

Example 2: javascript textarea.append

var $log = $('#myTextArea');

function log(text) {
    $log.append(text);
}

// Call log() in your button click event or whichever function 
// you want to use to print to the text area:

//...
log("Hello world!");
//...