Develop Reference

How to hide form submit button unless input is focussed (vanilla JS)

I have a form where I would like to hide the submit button unless the input is focussed/selected.
There is only one input apart from the submit.
I need to do this using pure JS (or perhaps CSS/Sass), not jQuery etc.
Basic example:
<form>
<input type="text" placeholder="Example field">
<input type="submit value="Submit">
</form>

First get references to your objects, so change the HTML for example :
<form>
<input id="input_1" type="text" placeholder="Example field">
<input id="submit" type="submit" value="Submit" />
</form>
With some CSS we will hide the submit by default:
#submit{
display:none;
}
We have added Id's, now we add the event listeners for focus on input..
document.getElementById("input_1").addEventListener('focus', function(){
document.getElementById("submit").style.display = 'block';
}
, true);
The second param into the eventListener will execute when the event is fired..
You will need to do more work on this..
https://jsfiddle.net/7uzkzr67/

Here is the pure CSS solution;
.showonfocus{
display:none;
}
.inputfield:focus + .showonfocus{
display:inline;
}
<form>
<input type="text" placeholder="Example field" class="inputfield">
<input type="submit" value="Submit" class="showonfocus">
</form>

You can use the onblur and onfocus events to manipulate your html elements. You can try something like,
HTML
<form>
<input type="text" placeholder="Example field" onblur="setVisible('hidden');" onfocus="setVisible('visible');">
<input id="submit" type="submit" value="Submit" style="visibility:hidden">
</form>
Javscript
function setVisible(state) {
document.getElementById("submit").style.visibility = state;
}
Here is the working DEMO: https://jsfiddle.net/qbotxpL6/
Hope this helps!

JS document.getElementById execute on Button click

I am extremely new to JavaScript, so bear with me.
I have the following code:
<input id="test" name="test" type="text" value="" />
<input id="test" type="button" value="Go!" />
<script type="text/javascript">
window.location.href="http://www.thenewendurancefitness.com/" + document.getElementById('test').value;
</script>
I would like the code to only be executed upon a button click. The function is to add the user input data to the end of the url and then upon the button click, load that url.
As of now, when I load the page, it automatically executes and goes to the url.

You have two input fields with the same ID, that's a no go!
Change the second one to something different!
Put your current javascript code into a function
function clickHandler(event) {
// Your code...
}
Attach an event listener to your container
var myContainer;
// assign element from DOM
myContainer = document.getElementById(ID_OF_CONTAINER);
// attach event handler
myContainer.addEventListener('click', clickHandler);
That should do the trick

<input id="test" name="test" type="text" value="" />
<input id="test2" type="button" onclick="fnc()" value="Go!" />
<script type="text/javascript">
function fnc(){
window.location.href="http://www.thenewendurancefitness.com/" + document.getElementById('test').value;
}
</script>

You need to wrap your code in a function, and then call the function based on an event. Here, the onclick event of the button. NOTE that IDs must be unique. Change your code to:
<input id="test" name="test" type="text" value="" />
<input id="test2" type="button" value="Go!" onclick="foo()" />
<script type="text/javascript">
function foo(){
window.location.href="http://www.thenewendurancefitness.com/" + document.getElementById('test').value;
}
</script>
jsFiddle example

Note that ID's are unique, and that you would use an event listener for that
<input id="test" name="test" type="text" value="" />
<input id="button" type="button" value="Go!" />
<script type="text/javascript">
document.getElementById('button').addEventListener('click', function() {
var val = document.getElementById('test').value;
window.location.href="http://www.thenewendurancefitness.com/" + val;
}, false):
</script>

<form onsubmit="return submit()">
<input id="test" name="test" type="text" value="" />
<input id="submit" type="submit" value="Go!" />
</form>
<script type="text/javascript">
function submit() {
location.href="http://www.thenewendurancefitness.com/"+document.getElementById('test').value;
}
</script>

JAVASCRIPT + HTML Button Value with getElements

I don't want to pass the value to the function, I want it to find the value itself.
<script type="text/javascript">
function add(buttonNum)
{
var elements = document.getElementsByTagName("button");
alert(document.myform.elements[buttonNum].value);
}
</script>
<form name="myform">
<input type="button" value="q" onclick="add(0)"/>
<input type="button" value="w" onclick="add(1)"/>
<input type="button" value="e" onclick="add(2)"/>
<input type="button" value="r" onclick="add(3)"/>
<input type="button" value="t" onclick="add(4)"/>
<input type="button" value="y" onclick="add(5)"/>
</form>
If I wanted to click on a button and display the value of the button into lets say a div; I don't want to code every button with an onclick(passing a parameter).
What approaches do I need to take? Something tells me that I need to get the length, run a for loop, and attach a handler. I'm just not sure on where to start.

simply pass this as parameter so that you can access all the attributes of the element but here only value:
<script type="text/javascript">
function add(elem)
{
alert(elem.value);
}
</script>
<form name="myform">
<input type="button" value="q" onclick="add(this)"/>
<input type="button" value="w" onclick="add(this)"/>
<input type="button" value="e" onclick="add(this)"/>
<input type="button" value="r" onclick="add(this)"/>
<input type="button" value="t" onclick="add(this)"/>
<input type="button" value="y" onclick="add(this)"/>
</form>

Compare:
getElementsByTagName("button");
<input>
You are getting the wrong element type.
If I wanted to click on a button and display the value of the button into lets say a div; I don't want to code every button with an onclick(passing a parameter).
Use addEventListener. You can identify the element clicked with event.target
e.g.
addEventListener('click', function (evt) {
if (evt.target.type == "button") {
alert(evt.target.value);
}
});

Input value hidden

I have this input:
<input id="tag1" type="text" name="tags" class="tags" value="#Model.list" />
and I want to get this input value in a hidden input, so I used this:
<input type="hidden" name="tag" value="tags" />
Instead of getting the true value of the first input, I only get the string "tags"! Can you please tell me how to obtain the true value of the first input in my hidden input? Thanks!
EDIT: Actually it's a submit page, the user enters tags in the #tag1 and when he clicks on submit I want to send these tags to my controller, that's why I'm using the hidden input...
My full code:
<form>
<p>
<input id="tag1" type="text" name="tags" class="tags" value="#Model.list" onblur="setValue()"; /></p>
<script>
$('#tag1').tagsInput({
// my parameters here
});
</script>
<style>
#wrapper {
margin: 20px;
}
</style>
<p>
<input type="submit" value="Create" />
<input type="hidden" name="taggg" id="tag2" />
<script type="text/javascript">
function setValue() {
document.getElementById("tag2").value = document.getElementById("tag1").value;
}
window.onload = setValue;
</script>
</p>
</form>

I don't understand why you would want to copy the value of one input field to another (albeit, hidden). But if that is what you want to do, try using the below code.
The function attached to the onblur event of the input field would set the value of the input field to the hidden field whenever it loses focus.
The window.onload = setValue will do the same on page load.
HTML
<input id="tag1" type="text" name="tags" class="tags" value="#Model.list" onblur="setValue();" />
<input type="hidden" name="tag" value="tags" id="tag1_hidden" /> <!-- Note the addition of an id attribute -->
JavaScript
function setValue() {
document.getElementById("tag1_hidden").value = document.getElementById("tag1").value;
}
window.onload = setValue;

Try this
<input id="tag1" type="text" name="tags" class="tags" value="#Model.list" />
<input type="hidden" name="tag" value="tags" id="tag2" />
Jquery:
$("#tag2").val($("#tag1").val());
or
$("#tag1").blur(function() {
$("#tag2").val($(this).val());
});

You can do like this (and you will need javascript for this).
Give a id to your hidden input also like:
<input type="hidden" id="hidden_input" name="tag" value="tags" />
and then use/paste this code when you need it:
var input_value = document.getElementById('tag1').value;
document.getElementById('hidden_input').value = input_value;

Change value of input and submit form in JavaScript

I'm currently working on a basic form. When you hit the submit button, it should first change the value of a field, and then submit the form as usual. It all looks a bit like this:
<form name="myform" id="myform" action="action.php">
<input type="hidden" name="myinput" value="0" />
<input type="text" name="message" value="" />
<input type="submit" name="submit" onclick="DoSubmit()" />
</form>
And this is how far I've come with the JavaScript code. It changes "myinput"'s value to 1, but it does not submit the form.
function DoSubmit(){
document.myform.myinput.value = '1';
document.getElementById("myform").submit();
}

You could do something like this instead:
<form name="myform" action="action.php" onsubmit="DoSubmit();">
<input type="hidden" name="myinput" value="0" />
<input type="text" name="message" value="" />
<input type="submit" name="submit" />
</form>
And then modify your DoSubmit function to just return true, indicating that "it's OK, now you can submit the form" to the browser:
function DoSubmit(){
document.myform.myinput.value = '1';
return true;
}
I'd also be wary of using onclick events on a submit button; the order of events isn't immediately obvious, and your callback won't get called if the user submits by, for example, hitting return in a textbox.

document.getElementById("myform").submit();
This won't work as your form tag doesn't have an id.
Change it like this and it should work:
<form name="myform" id="myform" action="action.php">

Here is simple code. You must set an id for your input. Here call it 'myInput':
var myform = document.getElementById('myform');
myform.onsubmit = function(){
document.getElementById('myInput').value = '1';
myform.submit();
};

No. When your input type is submit, you should have an onsubmit event declared in the markup and then do the changes you want. Meaning, have an onsubmit defined in your form tag.
Otherwise change the input type to a button and then define an onclick event for that button.

You're trying to access an element based on the name attribute which works for postbacks to the server, but JavaScript responds to the id attribute. Add an id with the same value as name and all should work fine.
<form name="myform" id="myform" action="action.php">
<input type="hidden" name="myinput" id="myinput" value="0" />
<input type="text" name="message" id="message" value="" />
<input type="submit" name="submit" id="submit" onclick="DoSubmit()" />
</form>
function DoSubmit(){
document.getElementById("myinput").value = '1';
return true;
}

My problem turned out to be that I was assigning as document.getElementById("myinput").Value = '1';
Notice the capital V in Value? Once I changed it to small case, i.e., value, the data started posting. Odd as it was not giving any JavaScript errors either.

I have done this and it works for me.
At first you must add a script such as my SetHolderParent() and call in the html code like below.
function SetHolderParent(value) {
alert(value);
}
<input type="submit" value="Submit" onclick="SetHolderParent(222);" />

You can use the onchange event:
<form name="myform" id="myform" action="action.php">
<input type="hidden" name="myinput" value="0" onchange="this.form.submit()"/>
<input type="text" name="message" value="" />
<input type="submit" name="submit" onclick="DoSubmit()" />
</form>

This might help you.
Your HTML
<form id="myform" action="action.php">
<input type="hidden" name="myinput" value="0" />
<input type="text" name="message" value="" />
<input type="submit" name="submit" onclick="save()" />
</form>
Your Script
<script>
function save(){
$('#myinput').val('1');
$('#form').submit();
}
</script>