Question

I don’t understand why my code doesn’t work.

I create dynamically groups of three buttons: the first button of the group has id 1, the second 101 and the third 201; buttons of the second group will be named respectively 2, 102 and 202, and so on.

If I want to delete all the three buttons by clicking the last one it works. This is what I set in the onclick event :

butt.onclick = function() {
    removeElement(this.id);
    removeElement(this.id-100);
    removeElement(this.id-200);
}

But if I want to delete all the three buttons by clicking the middle one with this onclick event:

butt.onclick = function() {
    removeElement(this.id+100);
    removeElement(this.id);
    removeElement(this.id-100);
}

it eliminates only buttons 1 and 101 but not 201.

It seems like it doesn’t like the “this.id+100” value. What’s the reason?

Thanks in advance.

Answer 1

Your mixing strings with numbers … and using the + with a string concatenates try

butt.onclick = function() {
    removeElement(parseInt(this.id,10)+100);
    removeElement(this.id);
    removeElement(parseInt(this.id,10)-100);
}

You use parseInt() to convert strings to numbers in JavaScript