Copy value from one textbox to another using submit button - javascript

I know this can be accomplished by Javascript, and I am learning so please tell me, when I click an update button I want the text from a textbox to be copied into another one.

Assuming you have this:
<textarea id="source"></textarea>
...
<textarea id="target"></textarea>
...
<button type="button" onclick="update();">Update</button>
Then your JS function can be:
function update() {
document.getElementById('target').value = document.getElementById('source').value;
}

jQuery solution - check it out (jQuery that is)
$('#button').click(function(e) {
e.preventDefault();
$('#totextarea').val($('#fromtextarea').val());
...then submit the form if you wish to or whatever...
$('#theform').submit();
});

Try the following
<script>
function onSubmitClick() {
var box1 = document.getElementById('box1');
var box2 = document.getElementById('box2');
box2.value = box1.value;
}
</script>
<textarea id='box1'></textarea>
<textarea id='box2'></textarea>
<button onclick='onSubmitClick(); return false'>Click Me</button>
JSFiddle Demo
http://jsfiddle.net/Wr8L8/

<script>
function sync()
{
// Take first and second value by element ID
var n1 = document.getElementById('n1');
var n2 = document.getElementById('n2');
// Assign the value of the 1st to the 2nd text box
n2.value = n1.value;
}
</script>
<input type="text" name="n1" id="n1" />
<input type="text" name="n2" id="n2"/>
<!-- you put a function sync to be executed on click on the button -->
<button onclick="sync()">Synchronize</button>

Related

Javascript getElementByID from form input

I am providing a form where the user shall enter an arithmetic calculation. Further down the result shall appear, once the user hits enter. It might just be a problem of syntax, but I couldn't find the mistake. Here is what I did so far:
<!DOCTYPE html>
<html>
<body>
<p>What do you want to calculate?</p>
<form method="post"><span>Type here:</span><input type="text" id="calc"></input>
</form>
<script>
num_field = document.getElementById("calc");
num_field.onsubmit=function ()
{
document.getElementById("display_result").innerHTML = num_field;
}
</script>
<p id="display_result"></p>
</body>
</html>
So, the user shall enter for instance "1+2". The result shall appear below.
Any idea where is my mistake?
Best regards
Here is how you can achieve that.
eval is the best way for doing that but eval is risky to use so make sure to sanitize the value of input before using eval.
I am using this regex /(^[-+/*0-9]+)/g to extract only numbers and few operators (-+/*) and doing eval on that value.
remove the <form> that is not required use keypress event listener and check for enter key. keycode of enter key is 13
num_field = document.getElementById("calc");
num_field.onkeypress = function(e) {
if(e.which==13)
{
var value = num_field.value.match(/(^[-+/*0-9]+)/g);
if(!value) return;
else value = value[0];
var res = eval(value);
document.getElementById("display_result").innerText = res;
}
}
<p>What do you want to calculate?</p>
<span>Type here:</span>
<input type="text" id="calc" />
<p id="display_result"></p>
You were nearly there, your code just needed a bit of tweaking - see below (comments in code as what I have done and why)
The following seems to be an alternate and safer way to do this without using eval (function taken from the second answer in this post):
<!DOCTYPE html>
<html>
<body>
<p>What do you want to calculate?</p>
<form method="post" id="form">
<span>Type here:</span>
<input type="text" id="calc"> <!-- inputs are self closing no need for closing tag -->
<input type="submit" value="submit"> <!-- added a submit button -->
</form>
<script>
form = document.getElementById("form");
num_field = document.getElementById("calc");
form.onsubmit = function() { // attach this event to the form
document.getElementById("display_result").innerHTML = evalAlternate(num_field.value); // add .value here to get the value of the textbox
return false; // return false so form is not actually submitted and you stay on same page (otherwise your display result will not be updated as the page is reloaded
}
function evalAlternate(fn) { // function safer alternate to eval taken from here: https://stackoverflow.com/questions/6479236/calculate-string-value-in-javascript-not-using-eval
fn = fn.replace(/ /g, "");
fn = fn.replace(/(\d+)\^(\d+)/g, "Math.pow($1, $2)");
return new Function('return ' + fn)();
}
</script>
<p id="display_result"></p>
</body>
</html>
see the below fiddle
https://jsfiddle.net/ponmudi/13y9edve/
num_field = document.getElementById("calc");
num_field.onkeydown = (event) => {
if (event.keyCode === 13) {
document.getElementById("display_result").innerHTML = eval(num_field.value);
return false;
}
}
This should work:
calc = document.getElementById("calc");
formula = document.getElementById("formula");
calc.addEventListener('click', function() {
document.getElementById("display_result").innerHTML = eval(formula.value);
});
<p>What do you want to calculate?</p>
<span>Type here:</span>
<input type="text" id="formula" />
<button id="calc" type="submit">calc</button>
<p id="display_result"></p>
eval() JavaScript Method
Try this:
var calculation_input = document.getElementById('calculation_input');
calculation_input.onkeydown = function(event) {
if (event.keyCode == 13) { // Enter key.
// Sanitize before using eval()
var calculation = calculation_input.value.replace(/[^-()\d/*+.]/g, '');
document.getElementById("display_result").innerHTML = eval(calculation);
}
}
<p>What do you want to calculate?</p>
<span>Type here:</span>
<input type="text" id="calculation_input" />
<p id="display_result"></p>
You don't need to submit the calculation in a form, you can just use native javascript to calculate the result. And don't forget to always sanitize before using eval :)

JS: How to print a value from a text box into the screen?

I want to print a value onto the screen based on text in the input (textbox) in the form.
<input type="text" name="pesos" value="">
<button onclick="conversorMonedas()">Convertir!</button>
<p id="resultado"></p>
function conversorMonedas() {
var pesos = document.getElementById("pesos");
document.getElementById("resultado").innerHTML = pesos.value;
}
When I click the button, the error at the console appears briefly and then disappears. I managed to read it and it says that pesos.value is null.
How can I print out what I wrote in the text box? Thanks!
You don't have element with id pesos. Add id to your input:
<input type="text" name="pesos" id="pesos" value="">
By using
var pesos = document.getElementById("pesos");
You're querying for something that has the id property set to pesos, looking at your HTML code you're not setting the id of your <input>
Simply add it, it should be like this:
<input type="text" id="pesos" name="pesos" value="">
There is no element with id pesos. So either add id="pesos" to input or modify your function to use getElementByNames as
$scope.conversorMonedas = function() {
var pesos = document.getElementsByName("pesos")[0];
document.getElementById("resultado").innerHTML = pesos.value;
}
But this may not work in cases you have multiple elements with this same name
<input id="input" type="text" name="text">
function Val() {
var x = document.getElementById("input").value;
document.getElementById("print1").innerHTML = x;
}
<input id="input" type="text" name="box">
<button id="btn" type="button" name="button"
onclick="Vale()">Post</button>
<span id="print1"></span>
var post = []
function Vale() {
const val = document.querySelector('input').value;
document.getElementById('input').value = "";
console.log(val);
post.push(val)
document.getElementById('print1').innerHTML = val
console.log(post);
}

Delete button next to each array's value

I have a HTML-JavaScript script in which the user can insert data to a new array [] by using a form's text field and an insert button.
By pressing insert button, the user inserts the data typed into the array.
I have a function which prints all the values of the array into <p id="demo"></p> and runs itself every 100 milliseconds in order to be updated with the arrays values.
I also have a reset button to delete every array's value when clicked.
What I want to do is add a delete button next to each array's value in order to be easier for the user to delete the wrong value he inserted.
I am using this code to insert values and print them:
HTML:
<div align="center">
<form id="form1">
<input type="text" name="fname" id="fname" placeholder="Type here!">
</form>
<br>
<input type="button" id="Button Insert" onclick="myFunction()" value="Insert">
<input type="button" onclick="myFunction3()" value="Reset">
</div>
<p id="demo" align="center"></p>
JavaScript/JQuery:
var all_values =[];
function myFunction() {
var temp_val = $("#fname").val();
all_values.push(temp_val);
document.getElementById("form1").reset();
}
setInterval(function () {
$("#demo").html(all_values.join("<br>"));
}, 100);
function myFunction3() {
all_values.length = 0;
}
To be more specific I want something like these things: iOS example JSFiddle Example 1 JSFiddle Example 2.
Could you please help me? Thanks in advance.
I'd do it the other way around.
Remove setInterval as it's really bad way to do such things.
Remove white spaces from the id attribute (id="Button-Insert", not id="Button Insert")
Don't use onclick attributes. Instead, register click event handlers with jQuery
// caching is a good practice when you reffer to the same elements multiple times:
var all_values =[], demo = $("#demo"), form = $("#form1")[0], fname = $("#fname");
$('#Button-insert').click(function(){
var temp_val = fname.val();
all_values.push(temp_val);
// create delete button along with the value
demo.append('<p>'+temp_val+' <button value="'+temp_val+'" type="button" class="del-btn">Delete</button></p>');
form.reset();
});
$('#Button-reset').click(function(){
all_values = [];
demo.html('');
});
// event delegation for dynamic elements:
demo.on('click', '.del-btn', function(){
all_values.splice(all_values.indexOf($(this).val()), 1);
$(this).parent().remove();
});
JSFiddle
Simply create the delete buttons at the same time you create the table.
function loadvalues(){
var i, button;
$('#demo').empty();
for(i in all_values){
$('#demo').append(all_values[i]);
button = $('<button>',{'text':'Delete'}).click(function(){
all_values.splice(this,1);
loadvalues();
}.bind(i)).appendTo('#demo');
$('#demo').append('<br>');
}
}
Also you don't need to poll, you could simply add each one on demand with a function like this:
function addVal(){
var val = $("#fname").val(), i = all_values.length;
all_values.push(val);
$('#demo').append(val);
button = $('<button>',{'text':'Delete'}).click(function(){
all_values.splice(this,1);
loadvalues();
}.bind(i)).appendTo('#demo');
$('#demo').append('<br>');
}
I had some typos, the code works,
Check here:
http://codepen.io/anon/pen/QbvgpW

Restore textfield's default value when user clicks the reset button JavaScript

I'm trying to get the textfields to return to their default value when the user clicks the Reset button.
All it does now when the user clicks the Reset button is replacing the user's text with ''.
How can I do it by using pure JavaScript (no jQuery)?
HTML:
<p>Type the first number</p>
<input id="first" type="text" placeholder="First Number" />
<p>Type the second number</p>
<input id="second" type="text" placeholder="Second Number" />
<button id="aButton">Apply</button>
<button id="rButton">Reset</button>
<div id="add"></div>
JAVASCRIPT:
app.onactivated = function (args) {
var aButton = document.getElementById("aButton");
aButton.addEventListener("click", buttonClickHandler, false);
var rButton = document.getElementById("rButton");
rButton.addEventListener("click", buttonResetHandler, false);
};
...
function buttonResetHandler(evetInfo) {
document.getElementById("first").innerText = '';
document.getElementById("second").innerText = '';
}
innerText is an invalid property that is implemented in IE browsers and is used for setting/getting text content of non-form elements, if the values should be set as default, you can use defaultValue property:
var a = document.getElementById("first"),
b = document.getElementById("second");
a.value = a.defaultValue;
b.value = b.defaultValue;
If you want to reset all the form elements, you can use .reset() method of DOM HTMLFormElement object:
document.forms["myForm"].reset();
location.reload(); // reloads the page
history.go(0); // deletes the history
But if you need to preserve some values inside of the page then reassign the values in the function again. To reassign, write the variable (declare in let to change later) again in the function and change the textContent again.
Replace,
document.getElementById("first").innerText
With,
document.getElementById("first").value
Example:
<input id="txtBox" type="text" value="lama">
<input type="button" value="reset lama" onclick='document.getElementById("txtBox").value="lama2";'>
create an init function that sets the default values for each input, then you can call that:
function initializeInputs() {
document.getElementById("first").value = '';
document.getElementById("second").value= '';
}
function buttonResetHandler(e) {
initializeInputs();
}

Add form input to array with javascript using unshift()

I am trying to add elements to an array via a form. I am using the unshift() method. The code below doesn't work and I would like to know why.
<form>
<input id="input"> </input>
<input type = "button" id="button"> Click me </input>
</form>
<script>
var input = document.getElementById("input").value;
var button = document.getElementById("button");
var myArray = [];
myArray.unshift(input);
button.onclick = function alerted (){
alert(myArray);
};
</script>
Your quoted code runs immediately when the page is loaded. The form field won't have anything in it then, so its value will be ''. When you alert that, the default toString operation on the array will result in '' and the alert will be blank.
You want to run your unshift code in response to a user event, such as the button being clicked, rather than right away. You can do that by setting input to be the element (remove .value from that line) and then moving your line with unshift into the function you're assigning to onclick, adding the .value there:
button.onclick = function alerted (){
myArray.unshift(input.value);
alert(myArray);
};
Other notes:
You never write </input>. Normally you don't close input tags at all. If you're writing XHTML (you probably aren't), you'd put the / within the main input tag like this: <input id="input" />. But again, you're probably not writing XHTML, just HTML.
The value (caption) of an input button goes in its value attribute, not content within opening and closing tags. (You would use opening and closing tags with the button element, not input.)
Taking all of that together, here's a minimalist update: Live copy | source
<form>
<input id="input"><!-- No ending tag -->
<input type = "button" id="button" value="Click me"><!-- No ending tag, move value where it should be -->
</form>
<script>
var input = document.getElementById("input"); // No .value here
var button = document.getElementById("button");
var myArray = [];
button.onclick = function alerted (){
myArray.unshift(input.value); // Moved this line, added the .value
alert(myArray);
};
</script>
DEMO
You need to a) get the value in the click and b) return false if you want the button to not submit. I changed to button. Alternative is <input type="button" value="click me" id="button" />
You may even want to empty and focus the field on click...
<form>
<input id="input" type="text"/>
<button id="button"> Click me </button>
</form>
<script>
var input = document.getElementById("input"); // save the object
var button = document.getElementById("button");
var myArray = [];
button.onclick = function alerted (){
myArray.unshift(input.value); // get the value
alert(myArray);
return false;
};
</script>​
You're not getting the new value in the onclick function.
Try this: http://jsfiddle.net/SeqWN/4/
var button = document.getElementById("button");
var i = document.getElementById("input");
var myArray = [];
button.onclick = function alerted (){
myArray.unshift(i.value);
alert(myArray);
};​

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