根据标题名称更改样式

Question

I am working on a site and need to only show a div if the title = "something". I cannot seem to achieve it, I have tried jQuery and javascript, here is what I have now.

var title = document.getElementsByTagName("title")[0].innerHTML;
    console.log(title);
    document.getElementsByClassName("book-a-lane").elems[0].style.visibility=     "hidden";
    if(title === "Frisco, TX"){
    document.getElementsByClassName("book-a-lane").elems[0].style.visibility= "block";
    }

Answer 1

You can get the title much more easily via document.title .

You're inventing a property here:

document.getElementsByClassName("book-a-lane").elems[0]
// --------------------------------------------^^^^^

getElementsByClassName returns a list, it doesn't have an elems property. Also note that getElementsByClassName isn't as well supported as querySelector , which would be more useful here.

You can also simplify the code dramatically.

Here's an example:

document.querySelector(".book-a-lane").style.visibility =
  document.title === "Frisco, TX" ? "visible" : "hidden";

querySelector takes a CSS selector and returns the first matching element (or null ). There's also querySelectorAll , which returns a list of matching elements.

You might want document.title.trim() , but beware browser support for it.

Live example when it matches.

Live example when it doesn't.

Answer 2

The title variable's value can be fetched with this: var title = document.title .

The line inside your if statement is faulty because there's no such thing as visibility: block; . It's either display: block; or visibility: visible; .

This is the semi-improved version:

var title = document.title;
document.getElementsByClassName("book-a-lane")[0].style.visibility = "hidden";
if (title == "Frisco, TX") {
    document.getElementsByClassName("book-a-lane")[0].style.visibility = "visible";
}

You don't need to use .elms to access the elements.

You can even use the ? strategy to do a true/false switch:

document.getElementsByClassName("book-a-lane")[0].style.visibility = title == "Frisco, TX" ? "visible": "hidden";

Answer 3

Do you mean to do this?

var title = document.getElementsByTagName("title")[0].innerHTML;

document.getElementsByClassName("book-a-lane")[0].style.visibility="hidden";

if(title === "Frisco, TX"){
    document.getElementsByClassName("book-a-lane")[0].style.visibility= "block";
}

Notice the lack of elems . getElementsByClassName can be accessed with the array accessor directly.