Javascript to show sum = 0 when no item is present in the list

Question

I have used the below JavaScript code to get the sum value of list column and the display it in a div.

<script type="text/javascript">
 _spBodyOnLoadFunctionNames.push("Effort");   
function Effort(){
var effortSpent = document.getElementById("aggrWPQ3").lastElementChild.innerText;
var IntEffortSpent = effortSpent.substring(4);
var results = parseInt(IntEffortSpent) + 0;

document.getElementById("DIV").innerHTML=results ;

    };
</script>

This code works when there is some item in the list and it is able to get the sum value and display it in the div but when there is no item in the list,I want it to display 0 in the same div.

what is needed to be done?

Answer 1

Based you comment the solution should be

function Effort() {
    var results = 0;
    if (document.getElementById("aggrWPQ3")) {
        var effortSpent = document.getElementById("aggrWPQ3").lastElementChild.innerText;
        var IntEffortSpent = effortSpent.substring(4);
        results = parseInt(IntEffortSpent) + 0;
    }
    document.getElementById("DIV").innerHTML = results
};

I am assuming that document.getElementById("aggrWPQ3") is undefined. document.getElementById("aggrWPQ3").lastElementChild could be undefined also. In that case, solution should be

function Effort() {
    var results = 0;
    if (document.getElementById("aggrWPQ3").lastElementChild) {
        var effortSpent = document.getElementById("aggrWPQ3").lastElementChild.innerText;
        var IntEffortSpent = effortSpent.substring(4);
        results = parseInt(IntEffortSpent) + 0;
    }
    document.getElementById("DIV").innerHTML = results
};

Let me know which one has worked.