Need to remove spaces, single quotes, and parens from a string displayed in as an <li>
This works great for the first two:
var foo = li.replace(/\s|\'+/g, "");
I assumed all I needed to do was add another few ORs to this, escaping the ( or ) symbols to search for them:
var foo = li.replace(/\s|\'+/g|\(|\), "");
Compiler no likey:
Uncaught SyntaxError: Unexpected token ILLEGAL
It appears the the that the open and closing paren are getting evaluated anyway - even with the escape symbols. What am I doing wrong here? Thanks!
You don't have the right syntax for regex literals. They're written as
/pattern/flags
And what you seem to want isn't a bunch of OR but a character class.
Use
var foo = li.replace(/[\s'()]+/g, "");
Related
Got error:
missing ) after the argument list
$('.next-btn').append("<a class="actionsubmit" ng-click="onSubmit('hello.html')">Check</a>");
It looks like you need to escape special characters inside your append string,
$('.next-btn').append("<a class=\"actionsubmit\" ng-click=\"onSubmit('hello.html')\">Check</a>");
The error is generated by syntax issues.
Your Code:
$('.next-btn').append("<a class="actionsubmit" ng-click="onSubmit('hello.html')">Check</a>");
You cannot use " inside this string without escaping it. For example:
$('.next-btn').append("<a class=\"actionsubmit\" ng-click=\"onSubmit('hello.html')\">Check</a>");
Please read: https://www.w3schools.com/js/js_strings.asp
Because strings must be written within quotes, JavaScript will misunderstand this string:
var x = "We are the so-called "Vikings" from the north.";
The string will be chopped to "We are the so-called ". The solution to avoid this problem, is to use the backslash escape character. The backslash (\) escape character turns special characters into string characters.
Now you can also create the element in jQuery. Advised code:
var newA = $("<a>", {
class: "actionsubmit",
"ng-click": "onSubmit('hello.html')"
}).html("Check");
$('.next-btn').append(newA);
Hope that helps.
I know this question had been asked lot of time but i could not find solution. I have some smilies which each of them has code to be rendered as smiley using replace() , but I get syntax error, I don't know why and how to render my code :/ to smiley
txt = " Hi :/ ";
txt.replace("/\:/\/g","<img src='img/smiley.gif'>");
Your regular expression doesn't need to be in quotes. You should escape the correct / forward slash (you were escaping the wrong slash) and assign the replacement, since .replace doesn't modify the original string.
txt = " Hi :/ ";
txt = txt.replace(/:\//g,"<img src='img/smiley.gif'>");
Based on jonatjano's brilliant deduction, I think you should add a little more to the regular expression to avoid such calamities as interfering with URLs.
txt = txt.replace(/:\/(?!/)/g,"<img src='img/smiley.gif'>");
The above ensures that :// is not matched by doing a negative-lookahead.
There are two problems in the first argument of replace() it escapes the wrong characters and it uses a string that seems to contain a regex instead of a real RegExp.
The second line should read:
txt.replace(/:\//g,"<img src='img/smiley.gif'>");
/:\//g is the regex. The first and the last / are the RegExp delimiters, g is the "global" RegExp option (String.replace() needs a RegExp instead of a string to do a global replace).
The content of the regex is :/ (the string you want to find) but because / has a special meaning in a RegExp (see above), it needs to be escaped and it becomes :\/.
I have the following Javascript code to obtain the inner string from an RegExp:
Function.prototype.method = function (name,func){
this.prototype[name] = func;
return this;
};
RegExp.method('toRawString', function(){
return this.toString().replace(/^.(.*).$/,"$1");
});
The purpose of this, is to avoid in string double quoting. For example, if you have a Windows file path "C:\My Documents\My Folder\MyFile.file", you can use it like the following:
alert(/C:\My Documents\My Folder\MyFile.file/.toRawString());
However it is not working for ""C:\My Documents\My Folder\" since it causes syntax error. The only way to avoid it is to keep double quoting at the end of the string. Thus it will be written
alert(/C:\My Documents\My Folder\\/.toRawString());
The fact is any odd number of back slashes on the end of the string will be an error, so all ending back slashes must be double escaped. It will not be hard to use a multiple line small implementation, but are there any single RegExp solution?
NOTE
When using toRawString the RegExp object for this is usually NOT going to be used for any other purpose except for that method. I just want to use the syntax of RegExp to avoid double back slashes in source code. Unfortunately the ending double slashes cannot be easily avoid. I think another workaround is to force a space at the end but that is another question then.
UPDATE
I finally solved the "another question" and posted the code here.
OK, I get what you're trying to do! It's hacky : )
Try something like:
return this.toString().slice(1, -1).replace(/\\+$/, '\\')
Hope that helps.
If you want to include the double quotes in the string just wrap it with single quotes.
s = '"C:\\My Documents\\My Folder\\MyFile.file"'
console.log(s) // Output => "C:\My Documents\My Folder\MyFile.file"
This produces a syntax error:
/C:\My Documents\/
But that regular expression could be written correctly like this:
/C:\\My Documents\\/
Or like this:
new RegExp("C:\\\\My Documents\\\\")
I think your function is just fine and is returning a correct result. Regular expressions just can't end with an unpaired backslash. It's not that you're double escaping - you're just escaping the escape character.
This would produce an error too:
new RegExp("C:\\My Documents\\")
A regular expression like this, for instance, can't be written without a pair of backslashes:
/C:\\What/
Without the second backslash, \W would be interpreted as a special character escape sequence. So escaping the escape character isn't only necessary at the end. It's required anywhere it might be interpreted as the beginning of an escape sequences. For that reason, it might be a good rule of thumb to always use two backslashes to indicate a backslash literal in a regular expression.
the sample is like this:-
var encdata= escape('They're good at coding."Super". Its great!');
Now the error comes because it finds the closing apostrophe at they're instead at last.
It will work if i code the same as
var encdata= escape('They re good at coding."Super".Its great!');
Similarly if i use double quotes and give like
var encdata= escape("They're good at coding."Super".Its great!");
It will throw error at "super" but not at they're.
So, it should work when my text contains both double quotes and apostrophe.
And i can't wrap my text within as 'text' or "text".
So, i need an alternate solution for it
Escape the characters with \' or \";
var encdata = escape('They\'re good at coding."Super".Its great!');
var encdata = escape("They're good at coding.\"Super\".Its great!");
you need to use \" or \':
var encdata= escape("They're good at coding.\"Super\".Its great!");
or
var encdata= escape('They\'re good at coding."Super".Its great!');
you have to use a slash \ to escape the apostrophe inside the single quotes, or alternatively the open quotes inside the double quotes.
'They\'re good at coding."Super". Its great!'
"They're good at coding.\"Super\".Its great!"
This is true for almost every language ever. Adding a slash to characters lets it know that you want it to be a literal character instead of having a special meaning.
In Javascript, when I put a backslash in some variables like:
var ttt = "aa ///\\\";
var ttt = "aa ///\";
Javascript shows an error.
If I try to restrict user in entering this character, I also get an error:
(("aaa ///\\\").indexOf('"') != -1)
Restricting backslashes from user input is not a good strategy, because you have to show an annoying message to the user.
Why am I getting an error with backslash?
The backslash (\) is an escape character in Javascript (along with a lot of other C-like languages). This means that when Javascript encounters a backslash, it tries to escape the following character. For instance, \n is a newline character (rather than a backslash followed by the letter n).
In order to output a literal backslash, you need to escape it. That means \\ will output a single backslash (and \\\\ will output two, and so on). The reason "aa ///\" doesn't work is because the backslash escapes the " (which will print a literal quote), and thus your string is not properly terminated. Similarly, "aa ///\\\" won't work, because the last backslash again escapes the quote.
Just remember, for each backslash you want to output, you need to give Javascript two.
You may want to try the following, which is more or less the standard way to escape user input:
function stringEscape(s) {
return s ? s.replace(/\\/g,'\\\\').replace(/\n/g,'\\n').replace(/\t/g,'\\t').replace(/\v/g,'\\v').replace(/'/g,"\\'").replace(/"/g,'\\"').replace(/[\x00-\x1F\x80-\x9F]/g,hex) : s;
function hex(c) { var v = '0'+c.charCodeAt(0).toString(16); return '\\x'+v.substr(v.length-2); }
}
This replaces all backslashes with an escaped backslash, and then proceeds to escape other non-printable characters to their escaped form. It also escapes single and double quotes, so you can use the output as a string constructor even in eval (which is a bad idea by itself, considering that you are using user input). But in any case, it should do the job you want.
You have to escape each \ to be \\:
var ttt = "aa ///\\\\\\";
Updated: I think this question is not about the escape character in string at all. The asker doesn't seem to explain the problem correctly.
because you had to show a message to user that user can't give a name which has (\) character.
I think the scenario is like:
var user_input_name = document.getElementById('the_name').value;
Then the asker wants to check if user_input_name contains any [\]. If so, then alert the user.
If user enters [aa ///\] in HTML input box, then if you alert(user_input_name), you will see [aaa ///\]. You don't need to escape, i.e. replace [\] to be [\\] in JavaScript code. When you do escaping, that is because you are trying to make of a string which contain special characters in JavaScript source code. If you don't do it, it won't be parsed correct. Since you already get a string, you don't need to pass it into an escaping function. If you do so, I am guessing you are generating another JavaScript code from a JavaScript code, but it's not the case here.
I am guessing asker wants to simulate the input, so we can understand the problem. Unfortunately, asker doesn't understand JavaScript well. Therefore, a syntax error code being supplied to us:
var ttt = "aa ///\";
Hence, we assume the asker having problem with escaping.
If you want to simulate, you code must be valid at first place.
var ttt = "aa ///\\"; // <- This is correct
// var ttt = "aa ///\"; // <- This is not.
alert(ttt); // You will see [aa ///\] in dialog, which is what you expect, right?
Now, you only need to do is
var user_input_name = document.getElementById('the_name').value;
if (user_input_name.indexOf("\\") >= 0) { // There is a [\] in the string
alert("\\ is not allowed to be used!"); // User reads [\ is not allowed to be used]
do_something_else();
}
Edit: I used [] to quote text to be shown, so it would be less confused than using "".
The backslash \ is reserved for use as an escape character in Javascript.
To use a backslash literally you need to use two backslashes
\\
If you want to use special character in javascript variable value, Escape Character (\) is required.
Backslash in your example is special character, too.
So you should do something like this,
var ttt = "aa ///\\\\\\"; // --> ///\\\
or
var ttt = "aa ///\\"; // --> ///\
But Escape Character not require for user input.
When you press / in prompt box or input field then submit, that means single /.