js if exists in page code example

Example 1: js check if dom element exists

var myElement = document.getElementById("myElementID");

if(!myElement){
    //#myElementID element DOES NOT exist
}

if(myElement){
    //#myElementID element DOES exists
}

Example 2: if text exists in element using javascript

if (
  (
    document.documentElement.textContent || document.documentElement.innerText
  ).indexOf('Done successfuly') > -1
) {
  // Do something...
}