Javascript – control the working directory for

Using

$("a").attr("href", "http://www.google.com/")

will modify the href of all hyperlinks to point to Google. You probably want a somewhat more refined selector though. For instance, if you have a mix of link source (hyperlink) and link target (a.k.a. "anchor") anchor tags:

<a name="MyLinks"></a>
<a href="http://www.codeproject.com/">The CodeProject</a>

...Then you probably don't want to accidentally add href attributes to them. For safety then, we can specify that our selector will only match <a> tags with an existing href attribute:

$("a[href]") //...

Of course, you'll probably have something more interesting in mind. If you want to match an anchor with a specific existing href, you might use something like this:

$("a[href='http://www.google.com/']").attr('href', 'http://www.live.com/')

This will find links where the href exactly matches the string http://www.google.com/. A more involved task might be matching, then updating only part of the href:

$("a[href^='http://stackoverflow.com']")
   .each(function()
   { 
      this.href = this.href.replace(/^http:\/\/beta\.stackoverflow\.com/, 
         "http://stackoverflow.com");
   });

The first part selects only links where the href starts with http://stackoverflow.com. Then, a function is defined that uses a simple regular expression to replace this part of the URL with a new one. Note the flexibility this gives you - any sort of modification to the link could be done here.

Since 1.8.5 it's possible to seal and freeze the object, so define the above as:

const DaysEnum = Object.freeze({"monday":1, "tuesday":2, "wednesday":3, ...})

or

const DaysEnum = {"monday":1, "tuesday":2, "wednesday":3, ...}
Object.freeze(DaysEnum)

and voila! JS enums.

However, this doesn't prevent you from assigning an undesired value to a variable, which is often the main goal of enums:

let day = DaysEnum.tuesday
day = 298832342 // goes through without any errors

One way to ensure a stronger degree of type safety (with enums or otherwise) is to use a tool like TypeScript or Flow.

Quotes aren't needed but I kept them for consistency.