adding strings and numbers in javascript

Question

The script below is an example I came across in a tutorial. It's supposed to show what happens to a number when it gets too big.

<script>
function myFunction() {
    var myNumber = 2; 
    var txt = "";
    while (myNumber != Infinity) {
        myNumber = myNumber * myNumber;
        txt = txt + myNumber + "<br>";
    }
    document.getElementById("demo").innerHTML = txt;
}
</script>

And here is the output:

4
16
256
65536
4294967296
18446744073709552000
3.402823669209385e+38
1.157920892373162e+77
1.3407807929942597e+154
Infinity

My two questions are basically

1) In the second iteration of the while loop, txt already has a character 4 in it (because a string plus a number is a string in Javascript) and then we add 16 to that string. Shouldn't we get 416 and so on?

2) Why does the break (br) element need to have a quotation marks around it?

1) At 2nd iteration, your txt becomes 4 16 , so its not 416 — fuyushimoya
– fuyushimoya, Commented Jun 30, 2015 at 19:06
txt = txt + myNumber +  would be variable = variable + variable + variable and   is not a variable. — Leeish
– Leeish, Commented Jun 30, 2015 at 19:06

SLaks · Accepted Answer · 2015-06-30 19:06:30Z

4

1) No. In the second iteration, txt is "4 ". Adding 16 results in "4 16"

2) That's a string literal like any other string literal.

answered Jun 30, 2015 at 19:06

SLaks

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1 Comment

Leeish Over a year ago

@Rockstar5645 you are getting 416. You are just putting a   in between them like SLaks said. Thus there is a hard return between the two numbers. Add console.log(txt) inside the loop and you'll better see the numbers being added together.

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