Develop Reference

Find the output using typeof function

I am writing a code. And here I have a problem how can I fix that. I have an input line, it takes a string or a number. So I need to check what is the output and get the answer. I need to give a simple solution. So I can't use functions or something like that.
let input = prompt('Enter your text.');
if (typeof input === "string") {
alert("You have string.");
} else if (typeof input === "number" && input > 30) {
alert("number more than 30");
} else if (typeof input === "number" && input < 30) {
alert("number less then 30");
}

prompt will always return a string.
If you want to check whether the string is composed purely of numerical values, you could use a regular expression:
if (/^[+-]?\d+(?:\.\d+)?$/.test(input)) {
// then it's purely numerical
const num = Number(input.trim());
// perform more operations on the number
} else {
// it's not composed of only numerical characters
}
If you don't want to use a regex, you can use Number alone, but then you'll also include values like Infinity which might not be desirable, and since Number('') gives 0, you'll have to check for that separately:
const num = Number(input);
if (input.trim().length && !Number.isNaN(num)) {
// then it's a number, use num
}
Another approach that I'd recommend is to avoid prompt entirely. Consider using a proper modal instead, such as a form with an input box and a submit button.
In such a case, if you want to require a numeric input, just do:
<input type="number">

I had a similar problem a few weeks ago and this is what I did:
function testNumber(test) {
if (isNaN(test) === false) {
console.log("this is a number");
} else {
console.log("this is not a number");
}
}
testNumber(4); // number
testNumber("4") // number
testNumber("string") // not a number
You can replace "test" for a variable if you don't want to use a function
if (isNaN(myVar) === false) {}
And you may want to add more checks if you want to differentiate between 4 and "4"

You can do
let input = prompt('Enter your text.');
if(isNaN(Number(input))){alert("You have string.")};
if (Number(input) > 30) {
alert("number more than 30");
} else if (Number(input) < 30) {
alert("number less then 30");
}
So it can change all Stringed-numbers to numbers and check if they are number with the isNaN function

Why this regular expression return false?

i have poor eng, Sorry for that.
i'll do my best for my situation.
i've tried to make SignUpForm using regular expression
The issue is that when i handle if statement using the regular expression
result is true at first, but after that, become false. i guess
below is my code(javascript)
$(document).ready(function () {
var idCheck = /^[a-z]+[a-z0-9]{5,19}$/g; // more than 6 words
var pwCheck = /^(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{8,}$/; // more than 8 words including at least one number
var emCheck = /^([\w-]+(?:\.[\w-]+)*)#((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/; // valid email check
var signupConfirm = $('#signupConfirm'),
id = $('#id'),
pw = $('#pw'),
repw = $('#repw'),
email =$('#email');
signupConfirm.click(function () {
if(id.val() === '' || pw.val() === '' || email.val() === ''){
$('#signupForm').html('Fill the all blanks');
return false;
} else {
if (idCheck.test(id.val()) !== true) {
$('#signupForm').html('ID has to be more than 6 words');
id.focus();
return false;
} else if (pwCheck.test(pw.val()) !== true) {
$('#signupForm').html('The passwords has to be more than 8 words including at least one number');
pw.focus();
return false;
} else if (repw !== pw) {
$('#signupForm').html('The passwords are not the same.');
pw.empty();
repw.empty();
pw.focus();
return false;
}
if (emCheck.test(email.val()) !== true) {
$('#signupForm').html('Fill a valid email');
email.focus();
return false;
}
}
})
});
after id fill with 6 words in id input, focus has been moved to the password input because the condition is met.
but after i click register button again, focus move back ID input even though ID input fill with 6 words
i've already change regular expression several times. but still like this.
are there Any tips i can solve this issue?
I hope someone could help me.
Thank you. Have a great day

Do not use the global flag on your regexes. Your code should be:
var idCheck = /^[a-z]+[a-z0-9]{5,19}$/;
When you match with the /g flag, your regex will save the state between calls, hence all subsequent matches will also include the previous inputs.

use
var idCheck = /^[a-z]+[a-z0-9]{5,19}$/
removing the g flag
and modify the line
else if (repw.val() !== pw.val()) {

check if input form value (int) is less than expected

My question is about validating a form. I am doing a validation of two fields, one of them receives the value in decimal, example ($ 500.00), is already with mask.
In this field that receives the value, it can not be less than 300.00.
If it is smaller 300.00, a message will appear saying the value has to be greater than 300.00.
Summary: The validation checks that it is empty, but does not check if the (number) int is less than $ 300
I'm using it this way (there's more code, in short):
function valid_simulation(form1) {
if (form1.valor.value == ' ') {
alert("value is not valid");
return false;
}
if (form1.valor.value <= 300) {
alert("value is not valid");
return false;
}
}
Thanks for any help.

Your basic concept is correct: set the message when the if statement test is falsy. Something like the following:
function showFormError(message) {
$("#alertBox").text(message)
}
if (isInvalid) { showFormError("We have a problem.") }

If the dollar mark is the issue, You can split it and validate.
var userInput = $("#inputData").val();
if(userInput.includes("$")) {
var splitArray = userInput.split("$");
if (typeof splitArray[1] && parseFloat(splitArray[1]) < 300){
alert("Amount Not valid");
}
}

Javascript validation condition fails

The below java script condition works in two condition but one of the condition is not working properly.
Page has a field which allow user to enter either without wildcard or with wild card with two characters For eg: PA% or PAGTHYUR
If the user enter PAGTHYUR in the Search Field still the else condition alert is calling "There is delay processing times for broad wildcard searches" instead of directly submit the "searchType".
How to avoid the else alert if the user enter direct value(for eg:PAGTHYUR)
My Script is as below:
if(manufNo!="") {
var strLen = manuNo;
var wild = "%";
if(strLen.indexOf(wild) != -1 && strLen.indexOf(wild) < 2) {
alert("Enter atleast two characters before wildcard");
return false;
} else {
alert ("There is delay processing times for broad wildcard searches");
}
searchType = "manufNo";
}
Thanks in advance

Add an extra else if in case there is no wildcard, you just gotta figure out what you want to happen in that case:
if(manufNo!=""){
var strLen = manuNo;
var wild = "%";
if (strLen.indexOf(wild) === -1) {
//code for what happens when there is no wildcard
// potentially nothing?
} else if (strLen.indexOf(wild) < 2){
//well place wildcard
alert("Enter atleast two characters before wildcard");
return false;
} else {
//badly placed wildcard
alert ("There is delay processing times for broad wildcard searches");
}
searchType = "manufNo";
}

JAVASCRIPT HELP - code not working

My code isn't working, can someone please tell me what the problem is?
I'm guessing it's the for loop, but I cannot find the problem.
<html>
<body>
<script>
username = prompt("Please enter a your username:");
for (var i = 0; i < username; i++) {
if(isFinite(username.charAt(i))) {
result = true;
document.write("The username consists of one or more numbers." + BR);
}
else {
result = false;
document.write("The username must consist of one or more numbers." + BR);
}
}
</script>
</body>
</html>

You have two problems in your code:
In the for loop, use the length of the variable to establish the stop condition
for (var i = 0; i < username.length; i++)
BR is not defined
Working code: http://jsfiddle.net/f643fr4w/

From the output I can probably assume you just want to check if username consists of at least one number, actually: a digit.
// iterate over the input
for (var i = 0; i < username.length; i++) {
// check if it is a number (not a digit but that's the same here)
if (isFinite(username.charAt(i))) {
result = true;
// The requirement "one or more numbers" is fulfilled,
// we can break out of the loop
break;
}
else {
result = false;
}
// print something according to "result"
if(result === true){
document.write('The username consists of one or more numbers.');
} else {
document.write('The username must consist of one or more numbers.');
}
}
You have to go over the full length of the string to find out if there's no number but not if you want to find out if there is any number in it.
Now, if you want to test if it consists of only digits you have to reword the requirements, they are a bit too ambiguous now.
Additional hints:
you need to check the input, you always have to check user input!
you need to be aware that JavaScript strings are UTF16. Rarely a problem but gets easily one if you iterate over JavaScript strings.
String.charAt() returns a character, not a number. Don't rely on the automatic conversions in JavaScript, you way too easily shoot yourself in the foot if you rely on it but also if you don't, so be careful.
please don't use document.write, use either the console if available or change the text-node of an HTML element.
With these points in mind you may get something like this:
// make a list of digits
var digits = ['0','1','2','3','4','5','6','7','8','9'];
// ask the user for a username
var username = prompt("Please enter a your username:");
// check input
if (username.length === 0) {
console.log('no username given');
} else {
for (var i = 0; i < username.length; i++) {
// indexOf searches for the same type, that's why the digits above
// are strings with quotes around them
if (digits.indexOf(username.charAt(i)) >= 0) {
result = true;
// The requirement "one or more numbers" is fullfilled,
// we can break out of the loop
break;
}
else {
result = false;
}
}
// print something according to "result"
if (result === true) {
console.log('The username consists of one or more numbers.');
} else {
console.log('The username must consist of one or more numbers.');
}
}
The above is one variation of many and could easily give rise to a heated discussion on some forums (not here! Of course not! ;-) ) but I hope it helps.

Use a regex for such shenanigans:
var username = prompt("username plz kk thx");
var result = /[0-9]/.test(username);
document.write("The username " + (result ? "consists" : "must consist") + " of one or more numbers");