app.js:56 Uncaught TypeError: Cannot read property 'addEventListener' of null code example
Example 1: Error: TypeError: Cannot read property 'addEventListener' of null at downLoaded (file:///convert.js:10:38)
if(cInputValue.value != "")
Example 2: Cannot read property 'addEventListener' of null
if (document.body.contains(document.getElementById('someid'))) {
// do what you need
}
// or
if (!document.visibilityState) {
// do what you need
}
// or
if (!document.getElementsByClassName('.someclass')){
// do what you need
}