So what I'm doing is creating a site that displays information about a person when you click a button. The information is displayed in a text box on a part of the page, and you can click the "Info" button next to the person's name to make the content appear in the text box. The issue I was having was that I couldn't get the content to disappear when I clicked the second "Info" button to get the other person's information to show up. I understand that a function had to be created to change the "display" property to "block" from "none." I understand the first two statements of the function, but once it gets to the "if...return" statement, I don't understand what's going on. 
Any help in explaining this would be great! 

Thanks! 

```
function resetBioVisi()
{
    var bioElem = document.getElementById("bio");
    var bios = bioElem.childNodes;
    if (bios.length == 0) return;
    for (var index = 0; index < bios.length; index++)
        if (bios[index].style !== undefined)
                bios[index].style.display="none";
}

```