Block Specific Words with Regular Expressions - javascript

I'm still learning about Regular expressions, still little bit confused using it.
My case :
I need block some specific word in input html with javascript or jquery.
Words i need to block is admin or administrator keyword, i don't want people using keyword like admin or administrator when create new account (username).
I need to block keywords like admin, 4dmin, adm1n, 4dm1n or even ADMIN, 4Dm1N..No matter user input in lowercase or uppercase or even numeric to replace letter "A" with numeric "4".
For now my code is :
var input = document.getElementById("inputUser");
input.onkeyup = function() {
input.value = input.value = input.value.replace(/(admin|4dmin|adm1n|4dm1n)/,"");
}
Please help dear masters, i'm stuck at this moment, any help i very appreciate.

You could write a regular expression without bars more easily by using character classes and the i flag (ignores casing):
input.value = input.value.replace(/[a4]dm[i1]n/ig, '');
Make sure to only use a single = - your current code duplicates input.value = input.value =.
But do keep in mind that you shouldn't be relying on Javascript alone to manage this - also verify the input before putting it in the database.

You can try this using regex
^(?!.*admin|.*4dmin|.*4dm1n).*$

You can keep an array of blacklisted words and onkeyup check if the value matches with any word in that array
var input = document.getElementById("inputUser");
var restrictedVal = ["admin", "4dmin", "adm1n", "4dm1n"]
input.onkeyup = function() {
if (restrictedVal.indexOf(input.value.toLowerCase()) !== -1) {
input.value = "";
}
}
<input type="text" id="inputUser">

Related

Match a decimal number and replace non numeric characters in javascript

I am using the the following function in javascript.
function chknumber(a) {
a.value = a.value.replace(/[^0-9.]/g, '', '');
}
This function replaces any non numeric character entered in a textbox on whose onkeyup i have called the above function. The problem is it allows this string as well
1..1
I want the function to replace the second dot character as well. Any suggestions will be helpful.
I don't advocate simplistically modifying fields while people are trying to type in them, it's just too easy to interfere with what they're doing with simple handlers like this. (Validate afterward, or use a well-written, thoroughly-tested masking library.) When you change the value of a field when the user is typing in it, you mess up where the insertion point is, which is really frustrating to the user. But...
A second replace can correct .. and such:
function chknumber(a) {
a.value = a.value.replace(/[^0-9.]/g, '').replace(/\.{2,}/g, '.');
}
That replaces two or more . in a row with a single one. But, it would still allow 1.1.1, which you probably don't want. Sadly, JavaScript doesn't have lookbehinds, so we get into more logic:
function chknumber(a) {
var str = a.value.replace(/[^0-9.]/g, '').replace(/\.{2,}/g, '.');
var first, last;
while ((first = str.indexOf(".")) !== (last = str.lastIndexOf("."))) {
str = str.substring(0, last) + str.substring(last+1);
}
if (str !== a.value) {
a.value = str;
}
}
Can't guarantee there aren't other edge cases and such, and again, every time you assign a replacement to a.value, you're going to mess up the user's insertion point, which is surprisingly frustrating.
So, yeah: Validate afterward, or use a well-written, thoroughly-tested masking library. (I've had good luck with this jQuery plugin, if you're using jQuery.)
Side note: The second '' in your original replace is unnecessary; replace only uses two arguments.
try with match method if your input is "sajan12paul34.22" the match function will return a array contain [12 , 34.22]
the array index [0] is used for getting first numeric value (12)
function chknumber(a) {
a.value = a.value.match(/[0-9]*\.?[0-9]+/g)[0];
}

how to use regex with user input variable

I am getting an array of objects using JSON and then my goal is to let the user search for a specific login. For this I want them to be able to type a letter and check each object login, if the letter is contained I want to display it.
In order to achieve this I worked on the following code:
var i;
var out="";
var exp=/d/g;
var result = " ";
for(i=0;i<users.length;i++){
result= exp.test(users[i].login);
if(result){
out+= users[i].login+ " ";
}
}
It works fine if I write the regex (in this case d) but once I try putting a variable inside the regex it wont work. How do I create a regex that will take the users input and work with the test function to perform the same task? Or idk if there is a better/more elegant solution for this. I know there are different regex questions already but I didn't find one that helped me.
Appreciate the help!
You're testing a literal string - that string is passed in by the user but it's still literal, not a regex.
So you should try:
if( users[i].login.indexOf(userInput) > -1)
This will pass if the given input is in the searched string.

Slip input type value live using javascript

i'm trying to live edit a text box value so that the result will be split every two character,
adding a column and starting from some default character.
what i have till now is this code, that obviously doesn't work:
$('#textboxtext').keyup(function (){
var text = $("#textboxtext").val();
//$(text).attr('maxlength', '12');
var splitted = text.match(/.{2}|.{1,2}/g);
var result = ("B8:27:EB:" + splitted.join(':'));
});
i need the live split and the default character inside the textbox but i really don't know where to start...
From your code, it seems like you're trying to create a text box that has some very specific behavior. It looks like it needs to format its value in such a way that it always begins with certain 'prefix' of B8:27:EB:, and every subsequent pair of characters is is separated by a :. This is actually a very complex behavior and you have to consider a number of different interactions (e.g. what happens when the user attempts to delete or modify the prefix). I usually try to avoid such complex controls if possible, however here is a quick implementation:
$('#textboxtext').keyup(function (e){
var prefix = "B8:27:EB:",
text = $(this).val(),
splitted, result;
if (text.indexOf(prefix) == 0)
text = text.substr(9);
else if (prefix.indexOf(text) == 0)
text = "";
text = text.replace(/:/g, '');
splitted = text.match(/.{1,2}/g) || [];
result = prefix + splitted.join(':');
$(this).val(result);
});
Demonstration
Type inside the text box and see what happens. Also note, there are all kinds of interaction that this implementation doesn't account for (e.g. right-clicking and pasting into the text box), but it's a start.

Using regex in javascript

I cannot get to work the following example of Regex in JavaScript. Regex is valid, was tested on some webs testing Regex expression.
I want it to check if input is in format: xxx,xxx,xxx.
It is alerting wrong input all the time. Thanks for any help.
var re = /[0-9a-zA-Z]+(,[0-9a-zA-Z]+)*/;
var toValidation = document.getElementsByName("txtSerial").value;
alert(toValidation);
if(!re.test(toValidation))
return true;
else
{
alert("Please insert valid text.");
return false;
}
document.getElementsByName("txtSerial") will return all elements by that name (node collection). Node collections do not have an attribute named value, thus, .value will be undefined (as can be seen by your alert).
Depending on your markup, you will want to use
document.getElementById("txtSerial")
or
document.getElementsByName("txtSerial")[0]
(although the last one is certainly not ideal).

Detect Once a Certain Word Has Just Been Entered in a Textarea

Considering features like EditArea's and CodeMirror's autocomplete, I was wondering if, like Dreamweaver, there is a way to detect if the last word you entered is in a certain list then provide the same kind of suggestion box but with the function's arguments. I imagine you would use a regular expression on the entire field or possibly split() the whole thing (or the current line) then use the length attribute of the array to find the last bit of text, then do something involving an indexOf-like operation; however, this seems like it would get a bit resource-intensive. It almost looks like I've answered my own question, but it always helps to fully explain one's quandary, especially publicly. There's gotta be a better solution than mine. I appreciate any input. Thank you.
Put the list of words to match in an object, have the text or options to display as the value. Then on keyup or keypress you can get the last word of the text area using a function like:
function showLastWord(id){
var el = document.getElementById(id);
var lastWord = el.value.match(/\w+$/);
return lastWord? lastWord[0] : '';
}
Then check if the word is in the list and do stuff appropriately.
Edit
A small example is:
<textarea onkeyup="showHelp(this);"></textarea>
<script>
var getLastWord = (function() {
re = /\w+$/;
return function (s){
var lastWord = s.match(re);
return lastWord? lastWord[0] : '';
}
}());
var keyWords = {foo:'foo was typed',bar:'bar was typed'};
function showHelp(el) {
var lastWord = getLastWord(el.value);
// Check for matching own property of keyWords
if (keyWords.hasOwnProperty(lastWord)) {
// Do stuff
console.log(keyWords[lastWord]);
}
}

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