Uncaught TypeError: Object 0 has no method 'addEventListener'
var A={};
A.addEventsToClassName=function(event,className,func)
{
var a=document.getElementsByClassName(className);
for(var b in a)
{
b.addEventListener(event,func,false);
}
};
Object b is meant to be an element object once the function is called later in the code. How can I prevent this error?
A for (var b in a) will give the property names within a, not the actual values; so you need to dererefence a when you want to use them.
a[b].addEventListener(event, func, false);
Also, it's an Array like data structure, so you should iterate it as such:
for (var i = 0; i < a.length; ++i) {
a[i].addEventListener(event, func, false);
}
b is not an object nor an element, it is a string ("0"). for...in gives you the keys not the value.
Don't use for(var b in a) to loop through a NodeList (it will loop through not only the properties of itself but also the properties inherited from its parent), do this instead:
for(var i = 0; i < a.length; a++){
a[i].addEventListener...
}
If you ask why, then take this for example,
for(var a in document.querySelectorAll("body")){
console.log(a);
}
>"0"
>"length"
>"item"
You can see that for...in does not work in this case since length and item are not actually in the list but still properties inherited.
The b is probably a index not your object . Perhaps you want write like this:
a[b].addEventListener(event,func,false);
