Answers for "javascript if exist"

javascript check if variable exists

if (typeof myVar !== 'undefined') {
    // myVar is defined
}

how to check if exists in javascript

if (typeof(elem) !== 'undefined') {

how to check if object exists in javascript

if (typeof maybeObject != "undefined") {
   alert("GOT THERE");
}

how to check if exists in javascript

if (elem != null) {