how to get the text inside textarea in js code example

Example 1: hi;ight word in textarea javascript

$(function(){
  $("#search").click(function(){
    var area   = $('#test');
    var findWord = "rhoncus";
    var index = area.val().indexOf(findWord);
    area.focus().prop({'selectionStart': index, 'selectionEnd': index+findWord.length})          
  })
})

Example 2: javascript find textarea

if(document.getElementsByTagName('textarea').length > 0) {

}