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Remove first folder in string

I have a folder path that always starts with a certain string which I want to remove. Let's say it looks like this:
my-bucket/2929023/32822323/file.jpg
I want it to look like this:
2929023/32822323/file.jpg
How would I do that? Thanks!

Using the functions substring and indexOf from String.prototype.
var str = "my-bucket/2929023/32822323/file.jpg";
console.log(str.substring(str.indexOf('/') + 1))

You could use a simple replace method if the string is only present once;
var string = "my-bucket/2929023/32822323/file.jpg";
var revisedString = string.replace('my-bucket/', '');
console.log(revisedString);
However, you're also able to use a Regex (regular expression) to remove it as well, something like;
var string = "my-bucket/2929023/32822323/file.jpg";
console.log(string.replace(/^my-bucket\//, ''));

Use a regex to rip the first one out. No substrings necessary.
var myString= "my-bucket/2929023/32822323/file.jpg";
myString = myString.replace(/^.+?[/]/, '');

how do I change the regex to get the desired one?

I need to check a string where at the end the to symbols are mandatory, first is '#' and the second is given with the t variable.
I have got this:
var t = 0;
var p = /^[a-z0-9A-Z_-]*#$/ + t.toString();
p.test("asdf2#0");
and get always 'false'
how to add the t String to the RegExp of p variable
Now, I have searched a bit and found out that people do use RegExp constructor:
var t = 0;
var re = new RegExp("^\/\\[a-z0-9A-Z_-]*#" + t.toString() + "\/\\$");
var z = re.test("asdf2#0");
in this case z is always 'false'.
what I am doing wrong? Can you please, also explain what \ means exactly and why and where to apply it in the RegExp.

$ signals the end of the input string, so you need to add the variable value before it. To do so you must use the explicit Regexp object instead of the simplified version. Try the following:
var t = 0;
var p = new RegExp("^[a-z0-9A-Z_-]*#" + t + "$");

What are all the backslashes you have in that regex? I assume some of them are being interpreted as characters, and they aren't in your test string. If you remove them, it works just fine.

need regex to get string before and after sepearted by a colon

I am having strings like following in javascript
lolo dolo:279bc880-25c6-11e3-bc22-3c970e02b4ec
i want to extract the string before : and after it and store them in a variable. I am not a regex expert so i am not sure how to do this.

No regex needed, use .split()
var x = 'lolo dolo:279bc880-25c6-11e3-bc22-3c970e02b4ec'.split(':');
var before = x[0]
var after = x[1]

Make use of split(),No need of regex.
Delimit your string with :,So it makes your string in to two parts.
var splitter ="lolo dolo:279bc880-25c6-11e3-bc22-3c970e02b4ec".split(':');
var first =splitter[0];
var second =splitter[1];

Passing regex modifier options to RegExp object

I am trying to create something similar to this:
var regexp_loc = /e/i;
except I want the regexp to be dependent on a string, so I tried to use new RegExp but I couldn't get what i wanted.
Basically I want the e in the above regexp to be a string variable but I fail with the syntax.
I tried something like this:
var keyword = "something";
var test_regexp = new RegExp("/" + keyword + "/i");
Basically I want to search for a sub string in a larger string then replace the string with some other string, case insensitive.
regards,
alexander

You need to pass the second parameter:
var r = new RegExp(keyword, "i");
You will also need to escape any special characters in the string to prevent regex injection attacks.

You should also remember to watch out for escape characters within a string...
For example if you wished to detect for a single number \d{1} and you did this...
var pattern = "\d{1}";
var re = new RegExp(pattern);
re.exec("1"); // fail! :(
that would fail as the initial \ is an escape character, you would need to "escape the escape", like so...
var pattern = "\\d{1}" // <-- spot the extra '\'
var re = new RegExp(pattern);
re.exec("1"); // success! :D

When using the RegExp constructor, you don't need the slashes like you do when using a regexp literal. So:
new RegExp(keyword, "i");
Note that you pass in the flags in the second parameter. See here for more info.

Want to share an example here:
I want to replace a string like: hi[var1][var2] to hi[newVar][var2].
and var1 are dynamic generated in the page.
so I had to use:
var regex = new RegExp("\\\\["+var1+"\\\\]",'ig');
mystring.replace(regex,'[newVar]');
This works pretty good to me. in case anyone need this like me.
The reason I have to go with [] is var1 might be a very easy pattern itself, adding the [] would be much accurate.

var keyword = "something";
var test_regexp = new RegExp(something,"i");

You need to convert RegExp, you actually can create a simple function to do it for you:
function toReg(str) {
if(!str || typeof str !== "string") {
return;
}
return new RegExp(str, "i");
}
and call it like:
toReg("something")

javascript regular expressions with variable content

I have a working reg expression that does a replace function based on the expression. It works perfect. It finds a specific string based on the beginning of the string and the expression. This is it:
str.replace(/\bevent[0-9]*\=/, "event");
what this does is it changes event=1 to event.
What if event was a variable word? What if I needed to look for conference also?
I have tried:
var type = "conference";
str.replace(/\b/ + type+ /[0-9]*\=/, "conference");
and:
str.replace(/\b/type/[0-9]*\=/, "conference");
neither worked.
how can I pass a javascript string into a regular expression?

Instead of writing a RegEx literal, use a string to create a new RegExp object:
str.replace(new RegExp('\b' + var + '[0-9]'), …)

You can do that with the RegExp Object:
str.replace(RegExp('\b' + reStr + '[0-9]*\='),StrToReplaceWith)

Create a new regex object with your variable.
read this...
http://www.w3schools.com/js/js_obj_regexp.asp