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replace – with - using replace()

I have been using
var str = "Artist - Song";
str = str.replace("-", "feat");
to change some texts to "-".
Recently, I've noticed another "–" that the above code fails to replace.
This "–" seems a bit longer than the normal "-".
Is there any way to replace the longer one with the shorter "-"?
Any help is appreciated. Thanks
EDIT.
This is how the rest of the code is written.
var befComma = str.substr(0, str.indexOf('-'));
befComma.trim();
var afterhyp = str.substr(str.indexOf("-") + 1);
var changefeat = befComma.toUpperCase();

This "–" seems a bit longer than the normal "-".
Is there any way to replace the longer one with the shorter "-"?
Sure, you just do the same thing:
str = str.replace("–", "-");
Note that in both cases, you'll only replace the first match. If you want to replace all matches, see this question's answers, which point you at regular expressions with the g flag:
str = str.replace(/-/g, "feat");
str = str.replace(/–/g, "-");
I'm not quite sure why you'd want to replace the longer one with the shorter one, though; don't you want to replace both with feat?
If so, this replaces the first:
str = str.replace(/[-–]/, "feat");
And this replaces all:
str = str.replace(/[-–]/g, "feat");

Give this a shot:
var str = "Artist – Song";
str = str.replace("–", "-"); // Add in this function
str = str.replace("-", "feat");
This should replace the slightly longer "–" with the shorter more standard "-".

JavaScript - strip everything before and including a character

I am relatively new to RegEx and am trying to achieve something which I think may be quite simple for someone more experienced than I.
I would like to construct a snippet in JavaScript which will take an input and strip anything before and including a specific character - in this case, an underscore.
Thus 0_test, 1_anotherTest, 2_someOtherTest would become test, anotherTest and someOtherTest, respectively.
Thanks in advance!

You can use the following regex (which can only be great if your special character is not known, see Alex's solution for just _):
^[^_]*_
Explanation:
^ - Beginning of a string
[^_]* - Any number of characters other than _
_ - Underscore
And replace with empty string.
var re = /^[^_]*_/;
var str = '1_anotherTest';
var subst = '';
document.getElementById("res").innerHTML = result = str.replace(re, subst);
<div id="res"/>
If you have to match before a digit, and you do not know which digit it can be, then the regex way is better (with the /^[^0-9]*[0-9]/ or /^\D*\d/ regex).

Simply read from its position to the end:
var str = "2_someOtherTest";
var res = str.substr(str.indexOf('_') + 1);

jQuery: How to trim new line and tab characters between words

Hi I am getting new line(\n) and tab(\t) characters between words and I was trying to trim those by using $.trim() function but its not working. So can anyone have some solution for this type of problem.
Ex:
var str = "Welcome\n\tTo\n\nBeautiful\t\t\t\nWorld";
alert($.trim(str));
the above code is not working.

str.replace(/\s+/g, " "); //try this
reference replace
\s matches any newline or tab or white-space

You can do this:
var str = "Welcome\n\tTo\n\nBeautiful\t\t\t\nWorld";
alert($.trim(str.replace(/[\t\n]+/g,' ')));
// results is "Welcome To Beautiful World"

That is expected. trim only takes care of leading and trailing whitespace.
Instead, use
str.split(/\s/).join(' ');
In your example, this returns
"Welcome To Beautiful World"

You can use replace with a regular expression :
var str = "Welcome\n\tTo\n\nBeautiful\t\t\t\nWorld";
alert($.trim(str.replace(/[\t\n]+/g, ' ')));
Demo

Regex to extract all digits after last occurrence of a special character

I want to extract all digits after last occurrence of character "-" so for example 311-1974-8 should return me 8 and 311-1974-348 should return 348
edit:
Added clarification from a comment:
actually it's an external tool which provides it's own inbuild functionalists and i have no other option but to use regex to extract this. No JS can be applied :(

This captures the last number.
var str = '311-1974-348';
var matches = str.match(/-(\d+)$/);
var match = matches ? matches[1] : null;
console.log("matched? " + match);

Try matching on /[^-]+$/, e.g.:
var s = '311-1974-348';
s.match(/[^-]+$/); // => ["348"]

You mentioned in a comment it's for an external tool so...
-([0-9]+)$
dunno how your tool handles captured groups or anything...

Why not simply spliting ?
var str = input.split('-').pop();

Try this /[0-9]+$/. It worked on both the inputs you provided.

Searching for a last word in JavaScript

I am doing some logic for the last word that is on the sentence. Words are separated by either space or with a '-' character.
What is easiest way to get it?
Edit
I could do it by traversing backwards from the end of the sentence, but I would like to find better way

Try splitting on a regex that matches spaces or hyphens and taking the last element:
var lastWord = function(o) {
return (""+o).replace(/[\s-]+$/,'').split(/[\s-]/).pop();
};
lastWord('This is a test.'); // => 'test.'
lastWord('Here is something to-do.'); // => 'do.'
As #alex points out, it's worth trimming any trailing whitespace or hyphens. Ensuring the argument is a string is a good idea too.

Using a regex:
/.*[\s-](\S+)/.exec(str)[1];
that also ignores white-space at the end

Have you tried the lastIndexOf function http://www.w3schools.com/jsref/jsref_lastIndexOf.asp
Or Split function http://www.w3schools.com/jsref/jsref_split.asp

Here is a similar discussion have a look

You can try something like this...
<script type="text/javascript">
var txt = "This is the sample sentence";
spl = txt.split(" ");
for(i = 0; i < spl.length; i++){
document.write("<br /> Element " + i + " = " + spl[i]);
}
</script>

Well, using Split Function
string lastWord = input.Split(' ').Last();
or
string[] parts = input.Split(' ');
string lastWord = parts[parts.Length - 1];
While this would work for this string, it might not work for a slightly different string, so either you'll have to figure out how to change the code accordingly, or post all the rules.
string input = ".... ,API";
here, the comma would be part of the "word".
Also, if the first method of obtaining the word is correct, ie. everything after the last space, and your string adheres to the following rules:
Will always contain at least one space
Does not end with one or more space (in case of this you can trim it)
then you can use this code that will allocate fewer objects on the heap for GC to worry about later:
string lastWord = input.Substring(input.LastIndexOf(' ') + 1);
I hope its help