Array: Uncaught TypeError: Cannot read property 'push' of undefined
Question
I am writing this program and have checked other similar posts too. But I have difficulty understanding how can I solve this?
Here is html
<body>
<h1>Hello!</h1> Please input start and end of your numbers
<input type="text" id="start" value="1" />
<input type="text" id="end" value="10" />
<button id="btn" onclick="MyFunc(document.getElementById('start').value, document.getElementById('end').value)">Click Me</button>
and here is JS script:
function MyFunc(start, end) {
for(i=start;i<end;i++)
{
var arr = [];
arr[i].push;
document.getElementById("demo").innerHTML = arr[i]);
}
}
I want to construct an array sequence from the first and last values input by user, and then show the array/perform some calculations. I have reviewed other answers at Stack, but couldn't sort out whats wrong with this.
Thank you.
2 answers
solution1
2 ACCPTED 2015-06-18 07:32:57
You are declaring an empty array var arr = [] . Right after that you are accessing its contents so for sure it doesn't have any contents so arr[i] is undefined .
I think what you are trying to do is
function MyFunc(start, end) {
document.getElementById("demo").innerHTML = "";
var str = "";
for(i = start; i <= end; i++) {
str += i;
}
document.getElementById("demo").innerHTML = str;
}
solution2
-3 2015-06-18 07:35:12
Change
var arr= [];
To
var arr= new Array(size); // size needs to be an integer value.
Also declare the array before the for loop
You always have to initialize an array before adding/removing elements from the same. Since the arr array was not defined, you got a TypeError
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