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Escaping apostrophe (single quote) character in javascript and html

I have a following situation:
I compose a string in javascript that include apostrophe character. That string is actually html code that is later attached to html using innerHTML method. So the code looks something like this:
var str = 'link'; (argument of the foo function is string)
And after that, this string is inserted into some html element like this:
dataHolder.innerHTML = str;
I've tried to escape ' character with ', ' and \u0027 but all of that is rendered as ' after innerHTML method is called, so when the method foo from the example above is called by clicking on link I always get javascript error saying: Uncaught SyntaxError: missing ) after argument list

You need to have both ' and " in your string, so you will need a third way to delcare a string, you can use template strings for that. Declare your ba'r string as a template string and escape its apostrophe using a backslash \:
document.querySelector('#myDiv').innerHTML =
'link';
function foo(data) {
console.log(data);
}
<div id="myDiv"></div>

use \' instead of ' inside the string, so it should be
var str = 'link';
However, this code is just correct in string format aspect. I think what you want could be
var str = 'link';

You can also use the backtick ` to avoid this problem:
var str = `link`;

How to prevent html attribute value from generating new line, my json string value breaks

I am inserting a json string value as a value of a button element attribute,
like for example below
var $json = JSON.stringify('{"Long_text":"This is \'my json string and soon..."}');
$("#button_id").attr('data-json', $json);
This works in some of my pages but when there is a single quote in the text even if it is escape with a slash the value in the element attribute creates newline and it breaks
like:
<button data-json="{"Long_text":"This is \' "
"my json string and soon..."}" >Click</button>
I have tried using
replace('/\r?\n|\r|\n/g/',''); //to replace multiple newlines
Even if I replace the double spaces it doesn't work because the attribute itself was malformed. So when I get the attribute and try to parse the json value it cause an error.
I have found this,"->Line break inside HTML tag attribute value" should I replace the spaces with this %0D%0A ? as suggested
to preserved newlines or spaces?
Any help or advise is well appreciated! Thanks!

I found a solution other than replacing the spaces with this %0D%0A
from this Line break inside HTML tag attribute value
var base64 =
{
encode: function utoa(str)
{
return window.btoa(unescape(encodeURIComponent(str)));
},
decode: function atou(str)
{
return decodeURIComponent(escape(window.atob(str)));
}
}
I tried this and it works, it also make the string non-readable since it is base64_encoded, it avoid the line breaks caused by spaces and quotes.
var $json = base64.encode(JSON.stringify('{"Long_text":"This is \'my json string and soon..."}'));
$("#button_id").attr('data-json', $json);
then get the value and convert it again,
var valid_json = JSON.parse(base64.decode($("#button_id").attr('data-json')));
Thanks!

Pass this and string as parameter in jquery function

I try to append this following tag which has an onclick function.
$("body").append('<img onclick="removeDynamicColumn(this,'someString')" src="css/images/builder/removeTDTR.png"/>');
In this function I am passing two parameters one is, the element itself and another one is string , if I enclose that string parameter with single quotes in JSP itself showing this error -
Syntax error on token "someString", invalid AssignmentOperator.
If I enclose with double quotes while calling that function I got this error -
SyntaxError: expected expression, got end of script

Missing Escape '\' character in your code.
Try that code;
$("body").append('<img onclick="removeDynamicColumn(this,\'someString\')" src="css/images/builder/removeTDTR.png"/>');

Try escape \
$("body").append('<img onclick="removeDynamicColumn(this,\'someString\')" src="css/images/builder/removeTDTR.png"/>');

let's assume we have an string in a variable like this:
var param = "somestring"
we can inject this variable to your example, this way:
$("body").append('<img onclick="removeDynamicColumn(this, \'' + param + '\')" src="css/images/builder/removeTDTR.png"/>');
G.L

You need to escape your quote marks.
Try using \ before the ' characters around someString.
\'someString\'

Why bind it like that - if you are using jQuery then you can use a delegated bind and then use data- attributes for your string:
var body = $("body");
// give your image a class and data attribute for your string
body.append('<img src="css/images/builder/removeTDTR.png" data-string="some string" class="click-image">')
// this is delegated bind
body.on('click', '.click-image', function() {
var image = $(this), // your image as a jquery object
someString = image.data('string'); // your string
// do your onclick action here
});

Split with this char : "\"

I have a problem with the .split() function , I have the following string:
var imageUrl = "Images\Products\randomImage.jpg";
And I want to split by the character "\", but, this happens:
//If dont use double "\\", throws me an error.
var imageUrlArray = imageUrl.split("\\");
Then the variable has this value:
"ImagesProductsrandoImage.jpg"
I need to do that, because need to change this "\" into "/", because makes me an error with a plugin. The original String is obtained from the DataBase.

The first \ is escaping the second \ character. Your string should also be doubled up.
var imageUrl = "Images\\Products\\randomImage.jpg";
var updated = imageUrl.replace(/\\/g,"/");
console.log(updated);

You need to escape the file string so that the backslashes there become "\", then you can preform your split, and then un-escape the resulting array of strings for other characters that may have been backslashed.
Not too familiar with Javascript but it probably looks something like this:
$fileName = escape($fileName)

Escaping single quotes in JavaScript string for JavaScript evaluation

I have a project, in which some JavaScript var is evaluated. Because the string needs to be escaped (single quotes only), I have written the exact same code in a test function. I have the following bit of pretty simple JavaScript code:
function testEscape() {
var strResult = "";
var strInputString = "fsdsd'4565sd";
// Here, the string needs to be escaped for single quotes for the eval
// to work as is. The following does NOT work! Help!
strInputString.replace(/'/g, "''");
var strTest = "strResult = '" + strInputString + "';";
eval(strTest);
alert(strResult);
}
And I want to alert it, saying: fsdsd'4565sd.

The thing is that .replace() does not modify the string itself, so you should write something like:
strInputString = strInputString.replace(...
It also seems like you're not doing character escaping correctly. The following worked for me:
strInputString = strInputString.replace(/'/g, "\\'");

Best to use JSON.stringify() to cover all your bases, like backslashes and other special characters. Here's your original function with that in place instead of modifying strInputString:
function testEscape() {
var strResult = "";
var strInputString = "fsdsd'4565sd";
var strTest = "strResult = " + JSON.stringify(strInputString) + ";";
eval(strTest);
alert(strResult);
}
(This way your strInputString could be something like \\\'\"'"''\\abc'\ and it will still work fine.)
Note that it adds its own surrounding double-quotes, so you don't need to include single quotes anymore.

I agree that this var formattedString = string.replace(/'/g, "\\'"); works very well, but since I used this part of code in PHP with the framework Prado (you can register the js script in a PHP class) I needed this sample working inside double quotes.
The solution that worked for me is that you need to put three \ and escape the double quotes.
"var string = \"l'avancement\";
var formattedString = string.replace(/'/g, \"\\\'\");"
I answer that question since I had trouble finding that three \ was the work around.

Only this worked for me:
searchKeyword.replace(/'/g, "\\\'");//searchKeyword contains "d'av"
So, the result variable will contain "d\'av".
I don't know why with the RegEx didn't work, maybe because of the JS framework that I'm using (Backbone.js)

That worked for me.
string address=senderAddress.Replace("'", "\\'");

There are two ways to escaping the single quote in JavaScript.
1- Use double-quote or backticks to enclose the string.
Example: "fsdsd'4565sd" or `fsdsd'4565sd`.
2- Use backslash before any special character, In our case is the single quote
Example:strInputString = strInputString.replace(/ ' /g, " \\' ");
Note: use a double backslash.
Both methods work for me.

var str ="fsdsd'4565sd";
str.replace(/'/g,"'")
This worked for me. Kindly try this

The regular expression in the following code also handles the possibility of escaped single quotes in the string - it will only prepend backslashes to single quotes that are not already escaped:
strInputString = strInputString.replace(/(?<!\\)'/g, "\\'");
Demo: https://regex101.com/r/L1lF7J/1
Compatibility
The regex above uses negative lookbehind, which is widely supported but if using an older Javascript version, this clunkier regex (which uses a capturing group backreference instead) will also do the job:
strInputString = strInputString.replace(/(^|[^\\])'/g, "$1\\'");
Demo: https://regex101.com/r/9niyYw/1

strInputString = strInputString.replace(/'/g, "''");