var element = document.getElementById("test");
//If it isn't "undefined" and it isn't "null", then it exists.
if(typeof(element) != 'undefined' && element != null){
alert('Element exists');
} else{
alert('Element does not exist');
}
// HazaaZOOZ - javascript - check if the element exists in javascript
var myEle = document.getElementById("myElement");
if(myEle){
var myEleValue= myEle.value;
}