Develop Reference

how to update value in textarea after clicking a button?

I'm practicing JavaScript creating a convert case where I have a textarea where the initial text is informed and the second where the converted result should be output, I created a function to invert the text but when I click on the button that calls this function it doesn't convert if there is already a typed text.
How do I get it to update the values ​​when I click on the button?
function reverseText(){
function reverse(s){
var word = '';
for (var i = s.length - 1; i >= 0; i--)
word += s[i];
return word;
}
$('#input1').keyup(function(){
var text = $('#input1').val();
var newstring = reverse(text);
$('#input2').val(newstring);
});
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="convert-case">
<textarea id='input1'></textarea>
<textarea id='input2' readonly></textarea>
</div>
<div class="function-button">
<button onclick="reverseText()">reverse text</button>
</div>
I want to create other conversion functions so I want the value the user has already typed to be converted as soon as he clicks on one of the conversion options.

If I understand your question you want the button to directly convert the text. Right now you code is doing the reverse, but update the input only after user type a key.
You want to revert instantly on button click, and keep the update going
function reverseText(){
function reverse(s){
var word = '';
for (var i = s.length - 1; i >= 0; i--)
word += s[i];
return word;
}
function updateInput() {
var text = $('#input1').val();
var newstring = reverse(text);
$('#input2').val(newstring);
}
$('#input1').keyup(updateInput);
updateInput();
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="convert-case">
<textarea id='input1'></textarea>
<textarea id='input2' readonly></textarea>
</div>
<div class="function-button">
<button onclick="reverseText()">reverse text</button>
</div>

I don't really get what you want. If you want to get the value from input1, reverse the text and put it into input2 then just remove the first and last line of the code below
$('#input1').keyup(function(){
var text = $('#input1').val();
var newstring = reverse(text);
$('#input2').val(newstring);
});

Javascript form value restriction

I am trying to create a form which will store values in an empty array but the values must be between 0 to 5 and comma separated. the problem is it alerts if values is more than 5 but still stores the value in the array. I want it to alert and then restore the form value.
Here is my code:
<form name ="form1" onsubmit="return validateForm()">
<input type="number" name="text" id="inputText" name="inputText" />
<button onclick="pushData();">Insert</button>
<p id="pText"></p>
</form>
And javascript:
function validateForm () {
var form = document.forms["form1"]["inputText"].value;
if(form <0 && form >= 6) {
alert('value should must be between 0 to 5');
return false;
}
}
// create an empty array
var myArr = [];
function pushData() {
// get value from the input text
var inputText = document.getElementById('inputText').value;
// append data to the array
myArr.push(inputText);
var pval = "";
for(i = 0; i < myArr.length; i++) {
pval = pval + myArr[i];
}
// display array data
document.getElementById('pText').innerHTML = "Grades: " + pval ;
}

Try
if (form <0 || form >= 6)

I think it may work better if you reorganize where the functions are being bound.
Event propagation order:
The button is clicked, and the value is pushed into the array.
The form's submit event triggers, and validates the values, but it's too late.
There are many ways to approach this one, but the simplest would be to call pushData at the end of your validateForm.
Adjusted the condition, because there's no way for a number to
be less than 0 AND greater than or equal to 6 at the same time.
Also added event.preventDefault to stop form submission.
JavaScript
function validateForm (event) {
event.preventDefault();
var form = document.forms["form1"]["inputText"].value;
if (form < 0 || form > 5) {
alert('value should must be between 0 to 5');
return false;
}
pushData();
}
HTML
<form name="form1" onsubmit="validateForm(event)">
<input type="number" id="inputText" />
<button type="submit">Insert</button>
<p id="pText"></p>
</form>
JSFiddle

Note that per the MDN:
A number input is considered valid when empty and when a single number
is entered, but is otherwise invalid.
With this particular form element you may add min and max attributes so that the user must enter a value within a specified range. Therefore, the current contents of the OP's validateForm() function are superfluous. Additionally, that function has a problematic line of code:
if(form <0 && form >= 6) {
You cannot have a value that is both less than zero and greater than or equal to six. Use instead a logical OR, i.e. "||" operator for the logic to work.
The following code allows for a user to select numeric values in the range that the OP specifies and then it displays them in a comma-separated format, as follows:
var d = document;
d.g = d.getElementById;
var pText = d.g('pText');
pText.innerHTML = "Grades: ";
var inputText = d.g("inputText");
var myArr = [];
function pushData() {
var notrailingcomma = "";
myArr.push(inputText.value);
if (myArr.length > 1) {
notrailingcomma = myArr.join(", ").trim().replace(/,$/g,"");
pText.innerHTML = "Grades: " + notrailingcomma;
}
else
{
pText.innerHTML += inputText.value;
}
}
d.forms["form1"].onsubmit = function(event) {
event.preventDefault();
pushData();
};
p {
padding: 1em;
margin:1em;
background:#eeeeff;
color: #009;
}
<form name="form1">
<input type="number" id="inputText" name="inputText" min=0 max=5 value=0>
<button type="submit">Insert</button>
</form>
<p id="pText"></p>
A couple of points with respect to the form:
The OP's HTML has an error in the input field: it has two names. I dropped the one with a name of "text".
I like what #thgaskell recommends with respect to changing "Insert" into a submit button, preventing the default action of submitting the form, and associating pushData with the form's onsubmit event. So, I've modified the code accordingly.

Javascript check if input is a specific string

I have an HTML Input field and I need javascript to check if the input entered into this box is a certain string. Specifically, it has to be a specific Zip code, there are a total of 9 different zip codes, all which are different and in no numerical order. Once the code checks if it is that specific zip code, it returns "Yes", if not, simply no.
I know how to do this with ints, as shown in the code below, but not sure to how to do this with strings. This is my current code, which works with validating an integer between 1-10:
<input id="numb">
<button type="button" onclick="myFunction()">Submit</button>
<p id="demo"></p>
<script>
function myFunction() {
var x, text;
// Get the value of the input field with id="numb"
x = document.getElementById("numb").value;
// If x is Not a Number or less than one or greater than 10
if (isNaN(x) || x < 1 || x > 10) {
text = "Input not valid";
} else {
text = "Input OK";
}
document.getElementById("demo").innerHTML = text;
}
</script>

I think you are over-thinking this. You can just use the indexOf function to test your zip code array.
var btn= document.getElementById("btn");
var input = document.getElementById("numb");
var output = document.getElementById("demo");
var formArea = document.getElementById("formArea");
var zips = ["11111","22222","33333","44444","55555", "e1", "e2"];
btn.addEventListener("click", function() {
var result = null;
// indexOf() returns -1 when the supplied value isn't present
if(zips.indexOf(numb.value.toLowerCase()) > -1){
result = "yes";
// Show the form by removing the hidden class
formArea.classList.remove("hidden");
} else {
result = "no";
// Hide the form by adding the hidden class
formArea.classList.add("hidden");
}
output.textContent = result;
});
#formArea{
border:2px double grey;
width:50%;
box-shadow:2px 2px 0 #303030;
height:100px;
padding:5px;
}
.hidden {
display:none;
}
<input id="numb">
<button type="button" id="btn">Submit</button>
<p id="demo"></p>
<div id="formArea" class="hidden ">
Your form goes here
</div>

Can you use a regular expression for postal codes? Note this accounts for a set of zip codes that are in string format, but you are welcome to create a zip-code regex that can satisfy the set of zip codes you are interested in. And furthermore, if the set is small enough you can probably just enumerate them in a list/set and check if the set contains the input.
<input id="numb">
<button type="button" onclick="myFunction()">Submit</button>
<p id="demo"></p>
<script>
function myFunction() {
var x, text;
var isValidZip = /(^\d{5}$)|(^\d{5}-\d{4}$)/;
// Get the value of the input field with id="numb"
x = document.getElementById("numb").value;
// If x is Not a Number or less than one or greater than 10
if (!isValidZip.test(x)) {
text = "Input not valid";
} else {
text = "Input OK";
}
document.getElementById("demo").innerHTML = text;
}
</script>

convert it to a number
x = Number(document.getElementById("numb").value);

How to make a word a link if the user has input # before it?

I am using this code:
<form oninput="x.value=a.value">Account Info <br>
<input type="text" id="a">First Name<br>
UserName <output name="x" for="a"></output>
</form>
I want i such a way that if the user inputs a word and he has place # before the word without space then how to make the word as a link. Means the tag which happens in facebook. Can it be done with java script and how.
This was just the example to demonstrate i want to intergrate this type in my project as comments. And it will be with php.
Thanks

Here's one example to check. It works with enter keypress and even prevents for adding same tags over again: http://codepen.io/zvona/pen/KpaaMN
<input class='input' type="text" />
<output class='output'></output>
and:
'use strict';
var input = document.querySelector('.input');
var output = document.querySelector('.output');
input.addEventListener('keyup', function(evt) {
if (evt.keyCode !== 13 || !input.value.length || ~output.textContent.indexOf(input.value)) {
return;
}
var tag = document.createElement('a');
tag.appendChild(document.createTextNode(input.value));
if (input.value.startsWith("#")) {
tag.setAttribute("href", input.value);
}
output.appendChild(tag);
input.value = "";
}, false);

<form>Account Info <br>
<input type="text" id="a">First Name<br/>
<output id="result" name="x" for="a"></output>
<button type="button" onclick="changeVal(document.getElementById('a').value)">Click</button>
</form>
<script>
function changeVal(value1){
var dt = value1.split(" ");
document.getElementById("result").innerHTML = "";
for(var t=0; t < dt.length; t++){
if(dt[t].startsWith("#")){
document.getElementById("result").innerHTML = document.getElementById("result").innerHTML+" <a href='#'>"+dt[t]+"</a>";
}
else{
document.getElementById("result").innerHTML = document.getElementById("result").innerHTML+" "+dt[t];
}
}
}
</script>
Checkout Jsfiddle demo
https://jsfiddle.net/tum32675/1/

You could use a textarea to input and a render to show the output. Then hiding the input and showing the output only. But that's another
story.
If you use a contentEditable div, you can actually insert and render the html from it in the same component. Check it out!
$(document).on("keyup","#render", function(){
var words = $(this).text().split(" ");
console.log(words);
if (words){
var newText = words.map(function(word){
if (word.indexOf("#") == 0) {
//Starts with #
//Make a link
return $("<div/>").append($("<a/>").attr("href", "#").text(word)).html();
}
return word;
});
}
$(this).empty().append(newText.join(" "));
placeCaretAtEnd( $(this)[0]);
});
Here is the Plunker
Thanks for the attention.

Javascript calculator as users type numbers

I'm a noob at Javascript, but I'm trying to implement something on my website where users can type a quantity, and the subtotal updates dynamically as they type.
For example: if items are 10 dollars each, and a user types 5 in the text field I would like it to show $50 next to the text box. Pretty simple multiplication, but I don't know how to do it with Javascript. I think onKeyPress somehow? Thanks!

Assuming the following HTML:
<input type="text" id="numberField"/>
<span id="result"></span>
JavaScript:
window.onload = function() {
var base = 10;
var numberField = document.getElementById('numberField');
numberField.onkeyup = numberField.onpaste = function() {
if(this.value.length == 0) {
document.getElementById('result').innerHTML = '';
return;
}
var number = parseInt(this.value);
if(isNaN(number)) return;
document.getElementById('result').innerHTML = number * base;
};
numberField.onkeyup(); //could just as easily have been onpaste();
};
Here's a working example.

You should handle 'onkeyup' and 'onpaste' events to ensure you capture changes by keyboard and via clipboard paste events.
<input id='myinput' />
<script>
var myinput = document.getElementById('myinput');
function changeHandler() {
// here, you can access the input value with 'myinput.value' or 'this.value'
}
myinput.onkeyup = myinput.onpaste = changeHandler;
</script>
Similarly, use getElementById and the element's innerHTML attribute to set the contents of an element when you want to show the result.