What's wrong with this code? (Javascript)

Question

this code works, and it alerts the variable every time.

var idNumber;
var elements;
var id;
var blockerIds=[];
var whileLoop=0;
while (whileLoop<112) {
    elements=document.getElementsByName('bid');
    id=elements[whileLoop].getAttribute('id');
    blockerIds[whileLoop]=id;
    alert(blockerIds[whileLoop]);
    whileLoop++;
}

but I tried alerting it outside of the while statement, like this:

var idNumber;
var elements;
var id;
var blockerIds=[];
var whileLoop=0;
while (whileLoop<112) {
    elements=document.getElementsByName('bid');
    id=elements[whileLoop].getAttribute('id');
    blockerIds[whileLoop]=id;
    whileLoop++;
}
alert(blockerIds);

but it only says "undefined". Does anyone know how I can use this variable outside of the while statement, or does it seem like it should work perfectly?

You should probably put the document.getElementsByName() call outside of your loop. Just sayin'... — jgitter
– jgitter, Commented Feb 21, 2014 at 22:00
How many elements are there named bid? What are their ids? — Jacob Krall
– Jacob Krall, Commented Feb 21, 2014 at 22:00
there are 112 elements named bid, and there ids are "bid'x'_'x'" and x is always a number — CPC
– CPC, Commented Feb 21, 2014 at 22:01
use console.log() instead of alert, then you also see other error messages, when they occur. — spiehr
– spiehr, Commented Feb 21, 2014 at 22:01

Daniel · Accepted Answer · 2014-02-21 22:03:28Z

0

JSFiddle: link. Fixed your code:

var idNumber;
var elements;
var id;
var blockerIds=[];
var whileLoop=0;
elements=document.getElementsByName('bid');
while ((elements.length >= 112 && whileLoop < 112) || (whileLoop < elements.length && elements.length <= 112)) {
    id=elements[whileLoop].getAttribute('id');
    blockerIds[whileLoop]=id;
    whileLoop++;
}
alert(blockerIds);

answered Feb 21, 2014 at 22:03

Daniel

18.7k8 gold badges69 silver badges90 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Stan666 · Accepted Answer · 2014-02-21 22:06:50Z

0

JS is an interpreted language, when it runs, it firstly search all the definitions of var, and give them an undefined value. Even if the var is claimed to have a actual value, it will still be given an undefined value until this line has been eventually executed.

answered Feb 21, 2014 at 22:06

Stan666

4742 gold badges5 silver badges15 bronze badges

2 Comments

CPC Over a year ago

I don't understand that.

Stan666 Over a year ago

var idNumber; var elements; var id; var blockerIds=[]; var whileLoop=0; elements="123"; while (whileLoop < 3) { // less than 112     elements=document.getElementsByName('bid');     id=elements[whileLoop].getAttribute('id');     blockerIds[whileLoop]=id;     whileLoop++; } alert(blockerIds);

Collectives™ on Stack Overflow

What's wrong with this code? (Javascript)

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related