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Remove part of the string before the FIRST dot with js

I have the next problem. I need to remove a part of the string before the first dot in it. I've tried to use split function:
var str = "P001.M003.PO888393";
str = str.split(".").pop();
But the result of str is "PO888393".
I need to remove only the part before the first dot. I want next result: "M003.PO888393".
Someone knows how can I do this? Thanks!

One solution that I can come up with is finding the index of the first period and then extracting the rest of the string from that index+1 using the substring method.
let str = "P001.M003.PO888393";
str = str.substring(str.indexOf('.')+1);
console.log(str)

You can use split and splice function to remove the first entry and use join function to merge the other two strings again as follows:
str = str.split('.').splice(1).join('.');
Result is
M003.PO888393
var str = "P001.M003.PO888393";
str = str.split('.').splice(1).join('.');
console.log(str);

You could use a regular expression with .replace() to match everything from the start of your string up until the first dot ., and replace that with an empty string.
var str = "P001.M003.PO888393";
var res = str.replace(/^[^\.]*\./, '');
console.log(res);
Regex explanation:
^ Match the beginning of the string
[^\.]* match zero or more (*) characters that are not a . character.
\. match a . character
Using these combined matches the first characters in the string include the first ., and replaces it with an empty string ''.

calling replace on the string with regex /^\w+\./g will do it:
let re = /^\w+\./g
let result = "P001.M003.PO888393".replace(re,'')
console.log(result)
where:
\w is word character
+ means one or more times
\. literally .

many way to achieve that:
by using slice function:
let str = "P001.M003.PO888393";
str = str.slice(str.indexOf('.') + 1);
by using substring function
let str = "P001.M003.PO888393";
str = str.substring(str.indexOf('.') + 1);
by using substr function
let str = "P001.M003.PO888393";
str = str.substr(str.indexOf('.') + 1);
and ...

Replace multiple occurences of a comment with javascript

I want to replace multiple occurences of comment and try like below
JsFiddle
Code:
var str = '<!--#test--><!--#test1-->'
str = str.replace('<!--/g', '').replace('-->/g', '');
alert(str)

Your problem is that you're trying to use a string instead of a regular expression. For example, this works.
var str = '<!--#test-->'
str = str.replace(/<!--/g, '').replace(/-->/g, '');
alert(str)

Plain regex commands need to be inside //.
Also, use the
Disjunction; Alternative | (pipe character)
str = str.replace(/<!--|-->/g, ''); // #test#test1

String replace last character occurrence slash

My url looks like this: ://example/example/.com. I want to remove the last slash of the string. My attempt so far (but doesn't work):
.replace(/\/$/g, '');
Can someone help me along?

You have to escape the slash character in a regular expression literal. Capture the characters after the last slash until the end of the string and use in the replacement:
s = s.replace(/\/([^\/]*)$/, '$1');
(You don't need the g flag for this one, as you know that there is never more than one match.)
Demo: http://jsfiddle.net/Guffa/jkn52/
Alternatively, use a poositive look-ahead to match a slash that doesn't have another slash until the end of the string:
s = s.replace(/\/(?=[^\/]*$)/, '');
Demo: http://jsfiddle.net/Guffa/jkn52/2/

var str = "/1/2/3/4/5"
var index = str.lastIndexOf("/");
var newStr = str.substr(0, index ) + str.substr(index + 1);
console.log(newStr);
demo: http://jsfiddle.net/Jn9bm/

It's a little verbose, but it works:
var url = "//example/example/.com";
var slash_position = url.lastIndexOf('/');
url = url.substr(0, slash_position) + url.substr(slash_position+1);

Try This:
var s= someString.replace(/\//g, "");

Replace a substring with javascript

Need to replace a substring in URL (technically just a string) with javascript.
The string like
http://blah-blah.com/search?par_one=test&par_two=anothertest&SearchableText=TO_REPLACE
or
http://blah-blah.com/search?par_one=test&SearchableText=TO_REPLACE&par_two=anothertest
means, the word to replace can be either at the most end of the URL or in the middle of it.
I am trying to cover these with the following:
var newWord = NEW_SEARCH_TERM;
var str = 'http://blah-blah.com/search?par_one=test&SearchableText=TO_REPLACE&par_two=anothertest';
var regex = /^\S+SearchableText=(.*)&?\S*$/;
str = str.replace(regex, newWord);
But no matter what I do I get str = NEW_SEARCH_TERM. Moreover the regular expression when I try it in RegExhibit, selects the word to replace and everything that follows it that is not what I want.
How can I write a universal expression to cover both cases and make the correct string be saved in the variable?

str.replace(/SearchableText=[^&]*/, 'SearchableText=' + newWord)

The \S+ and \S* in your regex match all non-whitespace characters.
You probably want to remove them and the anchors.

http://jsfiddle.net/mplungjan/ZGbsY/
ClyFish did it while I was fiddling
var url1="http://blah-blah.com/search?par_one=test&par_two=anothertest&SearchableText=TO_REPLACE";
var url2 ="http://blah-blah.com/search?par_one=test&SearchableText=TO_REPLACE&par_two=anothertest"
var newWord = "foo";
function replaceSearch(str,newWord) {
var regex = /SearchableText=[^&]*/;
return str.replace(regex, "SearchableText="+newWord);
}
document.write(replaceSearch(url1,newWord))
document.write('<hr>');
document.write(replaceSearch(url2,newWord))

Regular Expression in JS

How do you trim all of the text after a comma using JS?
I have: string = Doyletown, PA
I want: string = Doyletown

var str = 'Doyletown, PA';
var newstr=str.substring(0,str.indexOf(',')) || str;
I added the || str to handle a scenario where the string has no comma

How about a split:
var string = 'Doyletown, PA';
var parts = string.split(',');
if (parts.length > 0) {
var result = parts[0];
alert(result); // alerts Doyletown
}

using regular expression it will be like:
var str = "Doyletown, PA"
var matches = str.match(/^([^,]+)/);
alert(matches[1]);
jsFiddle
btw: I would also prefer .split() method

Or more generally (getting all the words in a comma separated list):
//Gets all the words/sentences in a comma separated list and trims these words/sentences to get rid of outer spaces and other whitespace.
var matches = str.match(/[^,\s]+[^,]*[^,\s]+/g);

Try this:
str = str.replace(/,.*/, '');
Or play with this jsfiddle