Doubt On function($0,$1);
// $0,$1 two argument
My question is this two argument are Not defined But it hold some data on it ???
can any on help to Understand
how this two argument run;
function strip_tags(input, allowed) {
allowed = (((allowed || "") + "").toLowerCase().match(/<[a-z][a-z0-9]*>/g) || []).join('');
//console.log('----------->'+allowed.join('ss'));
var tags = /<\/?([a-z][a-z0-9]*)\b[^>]*>/gi,
commentsAndPhpTags = /<!--[\s\S]*?-->|<\?(?:php)?[\s\S]*?\?>/gi;
return input.replace(commentsAndPhpTags,'').replace(tags, function ($0, $1) { // need help to understand $0 , $1
//console.log('----------->'+$1);
return allowed.indexOf('<' + $1.toLowerCase() + '>') > -1 ? $0 : '';
});
}
That is a really bad way to sanitize markup. It's almost guaranteed to have some loopholes. A simpler way would just be to strip all markup:
var stripTags = function(str) {
return str.replace(/<[^>]+>/g, '');
};
As far as allowing specific elements goes, it would be better to write a tokenizer, iterate over the tokens, drop everything that's not allowed, and then output the markup from those tokens.
But if you don't care to write a tokenizer, this would be a better way of going about it, even though it's still kind of crude:
var allowed = { p: true, a: true };
var sanitize = function(str) {
return str.replace(/<\s*\/?\s*([^\s>]+)[^>]*>/g, function(tag, name) {
if (!allowed[name.toLowerCase()]) {
return '';
}
return tag;
});
};
But as the comment above mentions, if you're only sanitizing a user's markup on the client-side, it's a major problem. You need to be doing sanitization on the server-side.
return input.replace(commentsAndPhpTags, '').replace(tags, function (input, group1) {
//console.log('----------->'+group1);
return allowed.indexOf('<' + group1.toLowerCase() + '>') > -1 ? input : '';
});
You regex /<\/?([a-z][a-z0-9]*)\b[^>]*>/gi contains only a group match, which will be the content inside parentheses ([a-z][a-z0-9]*), replace() will pass to your function the original string and the group matches.
However, your regex should be like this /(<\/?[a-z][a-z0-9]*\b[^>]*>)/gi in order to be able to strip the tags.
Related
I'm trying to get better at javascript through codewars.com katas, and I came across an exercice in which things like element[i]=element[i].toLowerCase() doesn't change anything at all.
I would like to have some help with my code, here is the exercice's instructions followed by my code:
(Please note that I'm not very experienced with JS so the code may not be perfect at all)
A string is considered to be in title case if each word in the string
is either:
(a) capitalised (that is, only the first letter of the word
is in upper case) or
(b) considered to be an exception and put entirely into lower case unless it is the first word, which is always capitalised.
Write a function that will convert a string into title case, given an optional list of exceptions (minor words). The list of minor words will be given as a string with each word separated by a space.
Your function should ignore the case of the minor words string -- it should behave in the same way even if the case of the minor word string is changed.
Arguments:
First argument (required): the original string to be converted.
Second argument (optional): space-delimited list of minor words that must always be lowercase except for the first word in the string. The JavaScript/CoffeeScript tests will pass undefined when this argument is unused.
function titleCase(title, minorWords) {
if(title.length==0){return ""}
var titlesplit = title.split(" ")
if(minorWords){
minorWords=minorWords.split(" ")
}
var solutionstring = ""
titlesplit.forEach(element => myfunction(element,minorWords))
solutionstring[0] = solutionstring[0].toUpperCase()
return solutionstring
function myfunction(element,minorWords){
var elementlength= element.length
var i=0
if(minorWords && minorWords.includes(element)){
for(i;i<elementlength;i++){
element[i]=element[i].toLowerCase()
}
}else {
for(i;i<elementlength;i++){
if(i==0){element[i]=element[i].toUpperCase()}
else{element[i]=element[i].toLowerCase()}
}
}
if(solutionstring.length==0){solutionstring=solutionstring+element}else{solutionstring=solutionstring+" "+element}
return
}
}
As pointed out in comments, Strings are immutable in JavaScript.
Additionally, for searching use Maps instead of includes.
Likewise you can see what Set in JavaScript is and easily use Set here.
Added comments for you better understanding.
function titleCase(title, minorWords) {
// Use === for comparison
// Prefer using curly braces even for single statements
if (title.length === 0) {
return "";
}
var titlesplit = title.split(" ");
// Maps/Objects give O(1) search compared to arrays O(n)
// Key,value pairs - similar to dictionary
var minorWordsMap = {};
minorWords.split(" ").forEach(i => minorWordsMap[i.toLowerCase()] = true);
var finalWords = titlesplit.map((element, index) => convertCase(element, index));
finalWords[0] = toPascalCase(finalWords[0]);
return finalWords.join(" ");
function toPascalCase(s) {
s = s.split("");
s[0] = s[0].toUpperCase();
return s.join("");
}
function convertCase(element, index) {
const lElement = element.toLowerCase();
// If element is part of exception words, ignore
if(index !== 0 && minorWordsMap[lElement]) {
return element;
}
// If first element or not in exception list, send Title case
return toPascalCase(lElement);
}
}
Using javascript, im trying to make a node.js module to parse predicate logic statements.
I've been working on this regex for a bit and I just can't get it to behave the way i want
1. /\(((?:[^{}]*\([^{}]*\))*[^{}]*?)\)/
2. .replace(/\)((?:[^{}]*\)[^{}]*\))*[^{}]*?)\(/,'):::(')
the latter works fine on things like (a&s&d&a&s&d)->(a&s&(d)&s|(d)) but i just switched the delimiters...
what I'm trying to do is change a statement like
((r|a)&(s|r))&(~r)->(r|(q&r))->q
into
1->2->q
I can certainly write a procedural function to do it, that would be a fine solution. But Im really stuck on this.
The only real specification is the regex needs to respect the outermost parenthesis the most, and be able to replace separate ones.
Because this is not regex friendly I put togethor a couple of functions that do what you are looking for. The first matches parenthesis with depth:
function match_parens(code_to_test, level, opening, closing){
var sub_match, matched;
return code_to_test.replace(new RegExp('^([^'+opening+closing+']*(.))[\\s\\S]*$'), function(full_match, matched, $2, offset, original){
if ($2 == opening){
sub_match = match_parens(original.substr(offset+matched.length), level + 1, opening, closing);
matched = matched + sub_match
}
else if (level > 1){
sub_match = match_parens(original.substr(offset+matched.length), level - 1, opening, closing);
matched += sub_match;
}
return matched;
});
}
This function takes a string and returns everything up until the closing element.
The next function helps pulls a string passed to it apart, replacing all content in parenthesis with escalating numbers:
function pull_apart(testString){
var count = 1,
returnString = '',
tempIndex = testString.indexOf('(');
while (tempIndex !== -1){
returnString += testString.substring(0,tempIndex)+count;
count += 1;
testString = testString.substring(testString.indexOf('(') + match_parens(testString.substr(tempIndex + 1), 1, '(', ')').length+1)
tempIndex = testString.indexOf('(');
}
returnString += testString;
return returnString;
}
Running pull_apart('((r|a)&(s|r))&(~r)->(r|(q&r))->q') returns "1&2->3->q", which is what you are looking for. While this is not entirely regex, it is utilized in the paren matching function up above. I'm not sure if this fits whatever use case you had in mind, but hopefully it helps.
This question already has answers here:
Adding http:// to all links without a protocol
(4 answers)
Closed 8 years ago.
I would like to detect url's that are entered in a text input. I have the following code which prepends http:// to the beginning of what has been entered:
var input = $(this);
var val = input.val();
if (val && !val.match(/^http([s]?):\/\/.*/)) {
input.val('http://' + val);
}
How would I go about adapting this to only append the http:// if it contains a string followed by a tld? At the moment if I enter a string for example:
Hello. This is a test
the http:// will get appended to hello, even though it's not a url. Any help would be greatly appreciated.
This simple function works for me. We don't care about the real existence of a TLD domain to gain speed, rather we check the syntax like example.com.
Sorry, I've forgotten that VBA trim() is not intrinsic function in js, so:
// Removes leading whitespaces
function LTrim(value)
{
var re = /\s*((\S+\s*)*)/;
return value.replace(re, "$1");
}
// Removes ending whitespaces
function RTrim(value)
{
var re = /((\s*\S+)*)\s*/;
return value.replace(re, "$1");
}
// Removes leading and ending whitespaces
function trim(value)
{
return LTrim(RTrim(value));
}
function hasDomainTld(strAddress)
{
var strUrlNow = trim(strAddress);
if(strUrlNow.match(/[,\s]/))
{
return false;
}
var i, regex = new RegExp();
regex.compile("[A-Za-z0-9\-_]+\\.[A-Za-z0-9\-_]+$");
i = regex.test(strUrlNow);
regex = null;
return i;
}
So your code, $(this) is window object, so I pass the objInput through an argument, using classical js instead of jQuery:
function checkIt(objInput)
{
var val = objInput.value;
if(val.match(/http:/i)) {
return false;
}
else if (hasDomainTld(val)) {
objInput.value = 'http://' + val;
}
}
Please test yourself: http://jsfiddle.net/SDUkZ/8/
The best solution i have found is to use the following regex:
/\.[a-zA-Z]{2,3}/
This detects the . after the url, and characters for the extension with a limit of 2/3 characters.
Does this seem ok for basic validation? Please let me know if you see any problems that could arise.
I know that it will detect email address's but this wont matter in this instance.
You need to narrow down your requirements first as URL detection with regular expressions can be very tricky. These are just a few situations where your parser can fail:
IDNs (госуслуги.рф)
Punycode cases (xn--blah)
New TLD being registered (.amazon)
SEO-friendly URLs (domain.com/Everything you need to know about RegEx.aspx)
We recently faced a similar problem and what we ended up doing was a simple check whether the URL starts with either http://, https://, or ftp:// and prepending with http:// if it doesn't start with any of the mentioned schemes. Here's the implementation in TypeScript:
public static EnsureAbsoluteUri(uri: string): string {
var ret = uri || '', m = null, i = -1;
var validSchemes = ko.utils.arrayMap(['http', 'https', 'ftp'], (i) => { return i + '://' });
if (ret && ret.length) {
m = ret.match(/[a-z]+:\/\//gi);
/* Checking against a list of valid schemes and prepending with "http://" if check fails. */
if (m == null || !m.length || (i = $.inArray(m[0].toLowerCase(), validSchemes)) < 0 ||
(i >= 0 && ret.toLowerCase().indexOf(validSchemes[i]) != 0)) {
ret = 'http://' + ret;
}
}
return ret;
}
As you can see, we're not trying to be smart here as we can't predict every possible URL form. Furthermore, this method is usually executed against field values we know are meant to be URLs so the change of misdetection is minimal.
Hope this helps.
I'm using this regular expression for detect if an url ends with a jpg :
var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*[-A-Z0-9+&##\/%=~_|]*^\.jpg)/ig;
it detects the url : e.g. http://www.blabla.com/sdsd.jpg
but now i want to detect that the url doesn't ends with an jpg extension, i try with this :
var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*[-A-Z0-9+&##\/%=~_|]*[^\.jpg]\b)/ig;
but only get http://www.blabla.com/sdsd
then i used this :
var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*[-A-Z0-9+&##\/%=~_|]*[^\.jpg]$)/ig;
it works if the url is alone, but dont work if the text is e.g. :
http://www.blabla.com/sdsd.jpg text
Try using a negative lookahead.
(?!\.jpg)
What you have now, [^\.jpg] is saying "any character BUT a period or the letters j, p, or g".
EDIT Here's an answer using negative look ahead and file extensions.
Update
Knowing this is a "url finder" now, here's a better solution:
// parseUri 1.2.2
// (c) Steven Levithan <stevenlevithan.com>
// MIT License
// --- http://blog.stevenlevithan.com/archives/parseuri
function parseUri (str) {
var o = parseUri.options,
m = o.parser[o.strictMode ? "strict" : "loose"].exec(str),
uri = {},
i = 14;
while (i--) uri[o.key[i]] = m[i] || "";
uri[o.q.name] = {};
uri[o.key[12]].replace(o.q.parser, function ($0, $1, $2) {
if ($1) uri[o.q.name][$1] = $2;
});
return uri;
};
parseUri.options = {
strictMode: false,
key: ["source","protocol","authority","userInfo","user","password","host","port","relative","path","directory","file","query","anchor"],
q: {
name: "queryKey",
parser: /(?:^|&)([^&=]*)=?([^&]*)/g
},
parser: {
strict: /^(?:([^:\/?#]+):)?(?:\/\/((?:(([^:#]*)(?::([^:#]*))?)?#)?([^:\/?#]*)(?::(\d*))?))?((((?:[^?#\/]*\/)*)([^?#]*))(?:\?([^#]*))?(?:#(.*))?)/,
loose: /^(?:(?![^:#]+:[^:#\/]*#)([^:\/?#.]+):)?(?:\/\/)?((?:(([^:#]*)(?::([^:#]*))?)?#)?([^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/
}
};//end parseUri
function convertUrls(element){
var urlRegex = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*[-A-Z0-9+&##\/%=~_|])/ig
element.innerHTML = element.innerHTML.replace(urlRegex,function(url){
if (parseUri(url).file.match(/\.(jpg|png|gif|bmp)$/i))
return '<img src="'+url+'" alt="'+url+'" />';
return ''+url+'';
});
}
I used a parseUri method and a slightly different RegEx for detecting the links. Between the two, you can go through and replace the links within an element with either a link or the image equivalent.
Note that my version checks most images types using /\.(jpg|png|gif|bmp)$/i, however this can be altered to explicitly capture jpg using /\.jpg$/i. A demo can be found here.
The usage should be pretty straight forward, pass the function an HTML element you want parsed. You can capture it using any number of javascript methods (getElementByID, getElementsByTagName, ...). Hand it off to this function, and it will take care of the rest.
You can also alter it and add it tot he string protoype so it can be called natively. This version could be performed like so:
String.prototype.convertUrls = function(){
var urlRegex = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&##\/%?=~_|!:,.;]*[-A-Z0-9+&##\/%=~_|])/ig
return this.replace(urlRegex,function(url){
if (parseUri(url).file.match(/\.(jpg|png|gif|bmp)$/i))
return '<img src="'+url+'" alt="'+url+'" />';
return ''+url+'';
});
}
function convertUrls(element){
element.innerHTML = element.innerHTML.convertUrls();
}
(Note the logic has moved to the prototype function and the element function just calls the new string extension)
This working revision can be found here
Define the URL regex from the RFC 3986 appendix:
function hasJpgExtension(myUrl) {
var urlRegex = /^(([^:\/?#]+):)?(\/\/([^\/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?/;
var match = myUrl.match(urlRegex);
if (!match) { return false; }
Whitelist the protocol
if (!/^https?/i.test(match[2])) { return false; }
Grab the path portion so that you can filter out the query and the fragment.
var path = match[5];
Decode it so to normalize any %-encoded characters in the path.
path = decodeURIComponenent(path);
And finally, check that it ends with the appropriate extension:
return /\.jpg$/i.test(path);
}
This is a simple solution from the post of #Brad and don't need the parseUri function:
function convertUrls(text){
var urlRegex = /((\b(https?|ftp|file):\/\/|www)[-A-Z0-9+&##\/%?=~_|!:,.;]*[-A-Z0-9+&##\/%=~_|])/ig;
var result = text.replace(urlRegex,function(url){
if (url.match(/\.(jpg|png|gif|bmp)$/i))
return '<img width="185" src="'+url+'" alt="'+url+'" />';
else if(url.match(/^(www)/i))
return ''+url+'';
return ''+url+'';
});
return result;
}
The same result :
http://jsfiddle.net/dnielF/CC9Va/
I don't know if this is the best solution but works for me :D thanks !
Generally you can check all the extensions with some like (for pictures):
([^\s]+(\.(?i)(jpg|jpeg|png|gif|bmp))$)
the questions says it all :)
eg. we have >, we need > using only javascript
Update: It seems jquery is the easy way out. But, it would be nice to have a lightweight solution. More like a function which is capable to do this by itself.
You could do something like this:
String.prototype.decodeHTML = function() {
var map = {"gt":">" /* , … */};
return this.replace(/&(#(?:x[0-9a-f]+|\d+)|[a-z]+);?/gi, function($0, $1) {
if ($1[0] === "#") {
return String.fromCharCode($1[1].toLowerCase() === "x" ? parseInt($1.substr(2), 16) : parseInt($1.substr(1), 10));
} else {
return map.hasOwnProperty($1) ? map[$1] : $0;
}
});
};
function decodeEntities(s){
var str, temp= document.createElement('p');
temp.innerHTML= s;
str= temp.textContent || temp.innerText;
temp=null;
return str;
}
alert(decodeEntities('<'))
/* returned value: (String)
<
*/
I know there are libraries out there, but here are a couple of solutions for browsers. These work well when placing html entity data strings into human editable areas where you want the characters to be shown, such as textarea's or input[type=text].
I add this answer as I have to support older versions of IE and I feel that it wraps up a few days worth of research and testing. I hope somebody finds this useful.
First this is for more modern browsers using jQuery, Please note that this should NOT be used if you have to support versions of IE before 10 (7, 8, or 9) as it will strip out the newlines leaving you with just one long line of text.
if (!String.prototype.HTMLDecode) {
String.prototype.HTMLDecode = function () {
var str = this.toString(),
$decoderEl = $('<textarea />');
str = $decoderEl.html(str)
.text()
.replace(/<br((\/)|( \/))?>/gi, "\r\n");
$decoderEl.remove();
return str;
};
}
This next one is based on kennebec's work above, with some differences which are mostly for the sake of older IE versions. This does not require jQuery, but does still require a browser.
if (!String.prototype.HTMLDecode) {
String.prototype.HTMLDecode = function () {
var str = this.toString(),
//Create an element for decoding
decoderEl = document.createElement('p');
//Bail if empty, otherwise IE7 will return undefined when
//OR-ing the 2 empty strings from innerText and textContent
if (str.length == 0) {
return str;
}
//convert newlines to <br's> to save them
str = str.replace(/((\r\n)|(\r)|(\n))/gi, " <br/>");
decoderEl.innerHTML = str;
/*
We use innerText first as IE strips newlines out with textContent.
There is said to be a performance hit for this, but sometimes
correctness of data (keeping newlines) must take precedence.
*/
str = decoderEl.innerText || decoderEl.textContent;
//clean up the decoding element
decoderEl = null;
//replace back in the newlines
return str.replace(/<br((\/)|( \/))?>/gi, "\r\n");
};
}
/*
Usage:
var str = ">";
return str.HTMLDecode();
returned value:
(String) >
*/
Here is a "class" for decoding whole HTML document.
HTMLDecoder = {
tempElement: document.createElement('span'),
decode: function(html) {
var _self = this;
html.replace(/&(#(?:x[0-9a-f]+|\d+)|[a-z]+);/gi,
function(str) {
_self.tempElement.innerHTML= str;
str = _self.tempElement.textContent || _self.tempElement.innerText;
return str;
}
);
}
}
Note that I used Gumbo's regexp for catching entities but for fully valid HTML documents (or XHTML) you could simpy use /&[^;]+;/g.
There is nothing built in, but there are many libraries that have been written to do this.
Here is one.
And here one that is a jQuery plugin.