Button to increment value won't show the value? - javascript

I am trying to create a very basic JavaScript function that will increment a variable by 1 whenever it is clicked, and the variable will be displayed on the same page and show any updated value. I can't seem to get the variable to write to the HTML document, what am I doing wrong?
I assume the button works fine, but I don't think it is calling the function correctly:
function cookieClick(number) {
cookies = cookies + number;
document.getElementById("incrementValue").innerHTML = cookies;
}
Here's the Fiddle: https://jsfiddle.net/6aj2zxb6/

Change the JavaScript setting Load type to No Wrap - in head in jsfiddle
This is working fine
https://jsfiddle.net/6aj2zxb6/3/

You problem was solved by fiddle settings, but if you are interested, try this:
You can assign counter value into cookieClick property
function cookieClick(number) {
if(cookieClick.counter)cookieClick.counter=0;
cookieClick.counter += number;
document.getElementById("incrementValue").innerHTML = cookieClick.counter;
}
If you have var counter in the global (window) scope, it is more easy to overwrite it by another similar code. This is more safe solution. You can use it as a cache in future;-)

Related

Onclick function changes value

I want an easy way to set a variable value equal to n when function(n) runs.
Hovedkort
Prosessor
Arbeidsminne
I have this piece of HTML code. And I want the loadProdType function to change the value of a variable prodCat according to loadProdType's value. I tried the code under with and witout localstorage.setItem(loadCat, j). The js document is linked and there are no linking errors cause other pieces of code runs as it should.
var loadCat = 0
function loadProdType(j){
loadCat = j}
How can I set loadCat's value equal to loadProdType's value/parameter.
Thanks in Advance.
Edit:
Unsure how to set local storage for this but what I want the code to do is the following:
Change the value of variable prodCat according to the value of the onclick function.
Redirect to: products.html
When in products.html I run a piece of code that uses the prodCat value to choose a spesific index in an array.
All in all I just need to be able to change prodCat on one page(to the value of a funcion or with a onclick) and have it saved on the next.
Last edit
I'll create different functions for each onclick and try that with local storage.
You need either ? in the URL or local storage.
?
In main document:
location.href = "products.html?prodType=" + loadCat;
In products.html:
var loadCat = new URL(document.URL).searchParams.get("prodType");
localstorage
In main document:
window.localStorage.setItem("prodType", loadCat);
In products.html:
var loadCat = window.localStorage.getItem("prodType");

jQuery accessing updated values from variables on different events

I have a function which copies the values of a group of inputs to another group of inputs if the user clicks a button.
The function works fine but I'm having trouble with the vars I'm using to get the information. I want to use global variables because I want to use the same variables later on but it only works when I wrap those vars inside the function.
I've posted the two scenarios where it's working and not working below. Can anyone explain why I cannot access the correct value at that given time using a global variable?
EDITS: The 3 elements #admin-name, #admin-email and #admin-number are all present in the DOM when the script is called, as I am doing everything with document ready. I understand that when the script first runs these values will be blank because they haven't been filled out by the user yet. What I don't understand is why can't jQuery get the value once it has been filled out and I call the variable on the click function.
Not Working
var contactName = $('#contact-name').val();
var contactEmail = $('#contact-email').val();
var contactNumber = $('#contact-number').val();
$(".step-two .copy-details").on('click', function(){
$('#admin-name').val(contactName);
$('#admin-email').val(contactEmail);
$('#admin-number').val(contactNumber);
});
Working
$(".step-two .copy-details").on('click', function(){
var contactName = $('#contact-name').val();
var contactEmail = $('#contact-email').val();
var contactNumber = $('#contact-number').val();
$('#admin-name').val(contactName);
$('#admin-email').val(contactEmail);
$('#admin-number').val(contactNumber);
});
Man I struggled with this one, this post helped flesh it out for me, jQuery Global Variable. The problem is the variable called in the click function was still getting the original value of 0. To make the variable update when a new value is added you need to declare it and then wrap it in a change function like so:
JS
// declare the variable
var contactName;
// wrap it in a change function so the value updates
$('#contact-name').on('change', function(){
contactName = $('#contact-name').val();
});
// use the variable inside the function and it will show the updated value
$('.step-two').on('click', 'button', function(){
$('#admin-name').val(contactName);
console.log('contactName = ' + contactName);
});

dynamically generated js buttons with closures to assign onclick function parameters

I am running into a problem people have posted before: JavaScript dynamic parameters
But my code uses nodes rather than innerHTML assignments, so the existing SO post doesn't seem to apply to my code.
I want to dynamically generate HTML buttons in a table. For each button, I want to call a function with parameters that depend on the button's index/position in the table. First I tried just using lambda functions with the variable over which I was incrementing. This didn't work, so I also tried dynamically named variables, meaning each button should be passing a differently named variable to deal with lazy-loading effects. But this didn't work either. You can see both versions of what I tried in the code below:
This code I paste below is in a for-loop. In the following, I increase i by 1 each time. offset and jj are unchanged within the loop.
var variableDynamic = i.toString();
window['variableName' + variableDynamic] = i + offset;
upvote.onclick = function() {
upVoteA(i + offset, jj);
//upVoteA(window['variableName' + variableDynamic] , jj);
};
upvote.innerHTML = "Upvote"
Someone told me to look into closures, so following this recommendation: http://www.usepatterns.com/blog/javascript-closures I rewrote the onclick function declaration as:
upvote.onclick = function() {
var a = i + offset;
var b = kk;
function closeIt(){
upVoteA(a,b);
}
closeIt();
};
This still has the same effect that every button calls upVoteA with the same parameter, namely the last/highest value.
I realize I could refactor my code to turn these into .innerHTML set statements and then I'd print the variable and it would be set as a printed statement instead of a lazily-loaded variable. But I'd like not to do that if possible. (apologies that it's not technically lazy loading, the name seems reasonably apt)
Is there a way to make my code work? And why are the closures failing? I thought closures should preserve the environment they were created in, but that is not the case with my code. Which portion of the "environment" are preserved with closures?
This is a very bad answer, but it works
var funcStr = "function dummy() { upVoteA(" + (i + offset) + "," + jj + "); }";
eval(funcStr);
upvote.onclick = dummy;
But if you have something better, please let me know.

How do I display the value of a jQuery variable for testing?

I am working on a slider that uses jQuery. Some elements of the slider are working correctly, but there is a problem that I am trying to troubleshoot with some of the code. To test it I would like to be able to display the values of the variables in the statement.
Here is the code block I am working with:
$('.marquee_nav a.marquee_nav_item').click(function(){
$('.marquee_nav a.marquee_nav_item').removeClass('selected');
$(this).addClass('selected');
var navClicked = $(this).index();
var marqueeWidth = $('.marquee_container').width();
var distanceToMove = marqueeWidth * (-1);
var newPhotoPosition = (navClicked * distanceToMove) + 'px';
var newCaption = $('.marquee_panel_caption').get(navClicked);
$(' .marquee_photos').animate({left: newPhotoPosition}, 1000);
});
I added a div called 'test' where I would like to display the values of the variables to make sure they are returning expected results:
<div class="test"><p>The value is: <span></span></p></div>
For example, to test the values, I inserted this into the statement above:
$('.test span').append(marqueeWidth);
However, I don't get any results. What is the correct way to include a test inside that code block to make sure I am getting the expected results?
Thanks.
Just use JavaScript's console functions to log your variables within your browser's console.
var myVar = 123;
console.log(myVar, "Hello, world!");
If you're unsure how to open the console within your browser, see: https://webmasters.stackexchange.com/questions/8525/how-to-open-the-javascript-console-in-different-browsers
append is used to append either an HTML string, a DOM element, an array of DOM elements, or a jQuery element. Since you are just trying to show a number (marqueeWidth), you probably want to set the text of the span instead:
$('.test span').text(marqueeWidth);
Also, is there a particular reason why you don't just use the console? It may be worth reading over a Debugging JavaScript walkthrough.
you can use the following.
$('.test span').html(marqueeWidth);
However doing a console.log(yourvariable); or alert(yourvariable); is better.

Jquery global variable assignment and using in javascript function

I have a global variable listId(refer the below code) declared with a default value and then I am assigning it inside the jq("#nav1 li a").click(function() But once any of the other javascript function call takes place after this one, the listId does not reflect the changed value, instead its just the default value assigned during declaration. How can I make it reflect the changed values?
thanks
listId = 'x';
var jq=jQuery.noConflict();// for avoiding conflict
jq("#nav1").click(function(){
alert(this.id);
listId = this.id; //this.id is displayed in alert message
});
function pageSwitch(){
alert('on change id : '+listId);
//when called after the click function, this does not reflect changed values
}
The code you supplied worked for me. The listId variable was successfully changed to "nav1". I've written up a little test script, which changes listId to the div's id onClick, and then uses a function to change it back to "x". It works every time. Click here to test it.
Thanks guyz for the help..actually the function was invoked on click of an h:commandLink..so each time the page got reloaded and so did the js functions...I just used the a4j:commandLink and it worked fine...I should have presented the full picture..Sorry for that..will take care next time.

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