Develop Reference

How to make image give her name to text field then edit the name and save it? Plus delete button should remove picture

This one is very tricky and I cant imagine how to solve it... Request was "Double click on picture, then you get picture name in to text field. There you can change name and save it with button. Also there's another button which clicked you delete the picture."
At this moment I dont have much, it's just a guess what it should look like..
function rodytiViduryje(pav){
var paveikslas=document.getElementById("jap");
paveikslas.src=pav.src;
var aprasymas=document.getElementById("apr");
aprasymas.value=pav.title;
lastph=pav;
}
function keistiAprasyma(){
var NA=document.getElementById("apr");
lastph.title=NA.value;
}
function trintiPaveiskla(){
lastph.remove();
}
<div class="ketvirtas">
<!-- THIS PICTURE -->
<img id="jap" src="https://media.cntraveler.com/photos/60596b398f4452dac88c59f8/16:9/w_3999,h_2249,c_limit/MtFuji-GettyImages-959111140.jpg" alt=japonija class="b" style="width:780px;height:480px">
</div>
<div class="penktas">
<div class="aprasymas"> <!-- Buttons-->
<label for="tekstas">
<b>Paveikslo aprasymas</b>
</label><br/>
<input type="text" id="apr" />
<button id="saugoti" onclick="keistiAprasyma()">Išsaugoti aprašymą</button><br/>
<br>
<button onclick="trintiPaveiksla()">Trinti iš galerijos</button><br/>
</div>
</div>
Please share your ideas! :)

JS could be something like this (also made small changes to HTML):
document.addEventListener("DOMContentLoaded", function(event) {
let img = document.querySelector('#jap');
let descriptionInput = document.querySelector('#apr');
let saveButton = document.querySelector('#saugoti');
let deleteButton = document.querySelector('#trinti');
img.addEventListener('dblclick', function (e){
console.log
descriptionInput.value = this.alt;
});
saveButton.addEventListener('click', function(){
img.alt = descriptionInput.value;
});
deleteButton.addEventListener('click', function(){
img.remove();
});
});
<div class="ketvirtas">
<!-- THIS PICTURE -->
<img id="jap" src="https://media.cntraveler.com/photos/60596b398f4452dac88c59f8/16:9/w_3999,h_2249,c_limit/MtFuji-GettyImages-959111140.jpg" alt="japonija" class="b" style="width:780px;height:480px" />
</div>
<div class="penktas">
<div class="aprasymas"> <!-- Buttons-->
<label for="tekstas">
<b>Paveikslo aprasymas</b>
</label><br/>
<input type="text" id="apr" />
<button id="saugoti">Išsaugoti aprašymą</button><br/>
<br>
<button id="trinti">Trinti iš galerijos</button><br/>
</div>
</div>
My advice for future endeavours: scale your tasks to smaller ones. This will give you more valid results. Also you'll be able to learn while combining those multiple solutions to the one you need. I.e., your searches for this task could be:
Javascript double click event
Javascript get images' alt value
Javascript set images' alt value
Javascript remove DOM element

Error in download a div as PDF using Javascript on button click

I am trying to download cv as pdf on button click in my cv builder using JS but unfortunately, the function instead of being called on button click is called as soon as the page loads. I tried some other ways including the arrow function and onclick attribute of the button although after that downloading starts on the button click but the pdf turns out to be empty.
Code:
HTML:
<div class="container profile-box" id="f">
<!-- Code of whole cv template -->
</div>
<div class="col-md-12 text-center">
<button type="button" class="btn btn-primary" id="pdf" >Download Pdf</button>
</div>
JS:
var btnpdf=document.getElementById("pdf");
async function generatepdf(){
var downloading=document.getElementById("f");
let width1 = downloading.offsetWidth;
let height1 = downloading.offsetHeight;
var doc=new jsPDF('p','pt');
await html2canvas(downloading,{
allowTaint:true,
useCORS:true,
width:width1,
height:height1
}).then((canvas)=>{
//canvas convert to png
doc.addImage(canvas.toDataURL("image/png"),'PNG',10,10);
})
doc.save("cv.pdf");
}
btnpdf.addEventListener("click",generatepdf());

It works for me.
What error are you getting?
Did you include the jspdf?
<script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.3.2/jspdf.min.js"></script>

simple slide show in JS- buttons are not working properly

I want to create a basic page in html that displays a single image.
I also added two buttons Previous and Next. These buttons should allow the user to move forward or backward. Have 6 images in total. When the user reaches the end (or beginning when clicking on the back button) of the slide show, the slide show should not wrap around to the beginning (or end).
button onclick function for both the cases is not working. Its only getting displayed the first image as what mentioned in the img src attribute.
This is what I have done so far. I put all the images into an array and try to travel the array forward and backward side based on the button click.
<body>
<img src="img1.jpg" id="demo" style="width:400px;height:600px"/img>
<br/>
<input type="button" onclick="preImage()" value="Previous
">
<input type="button" onclick = "nextImage()" value="Next
">
<script>
var slider_content = document.getElementById("demo");
var image = ['img1','img2','img3','img4','img5','img6'];
var i = image.length;
function nextImage(){
if(i<image.length){
i=i+1;
}else{
i=1;
}
slider_content.innerHTML="<img src="+image[i-1]+".jpg>";
}
function preImage(){
if(i<image.length+1 && i>1){
i=i-1;
}else{
i=image.length;
}
slide_content.innerHTML = "<img src="+image[i-1]+".jpg">
}
</script>
</body>

Create a wrapper div to your image and change the innerHTML of the div.
<div id="demo" style="width:400px;height:600px">
<img src="img1.jpg">
</div>

An error needs to be corrected in the preImage function:
slide_content.innerHTML = "<img src="+image[i-1]+".jpg">
to
slider_content.innerHTML = "<img src="+image[i-1]+".jpg>";
and also what Daniel said.

Update html image via javascript functions

I'm fairly new to javascript, and getting quite frustrated by the following code
<!DOCTYPE html>
<html>
<script>
var time = '0'
var area = 'neast'
function update_area(input) {
area = input;
load_updated_image(area,time);
};
function update_time(input) {
time = input;
load_updated_image(area,time);
};
function load_updated_image(area,time) {
var url = 'http://personal.psu.edu/kps5442/modelimages/hrrr_'+area+'_wetbulb'+time+'.png';
document.getElementById("theImage").src = url;
document.getElementById("url").innerHTML = url;
};
</script>
<body onload="load_updated_image(area,time)">
<p>URL Output:</p>
<p id="url"></p>
<font size = 4><b>Forecast Hour: </b>
<font size = 3>
<a href="#" onmouseover="update_time(0);" /> 00</a>
<a href="#" onmouseover="update_time(1);" /> 01</a>
<a href="#" onmouseover="update_time(2);" /> 02</a>
<img id="theImage" src=undefined width="850" height="600" />
<br> <font size = 4><b>Region Selection: </b>
<a href="#" onclick="update_area(neast);" /> Northeast</a>
<a href="#" onclick="update_area(seast);" /> Southeast</a>
</body>
</html>
I have 18 different "hours" of images for different regions across the US. The goal is to change the hour of the image when the hour links are moused over, and update the region when the region links are clicked.
The function update_time() works as expected, changing the image as I mouse over the links. However, the function update_area() fails with the following error:
"Uncaught ReferenceError: neast is not defined"
I'm not sure why this is happening, because the update_time and update_area functions are built in exactly the same way, and I globally defined the time and area variables at the start of the script.
Any help would be appreciated!

You have to put the arguments in quotes .
onclick="update_area('neast');"
onclick="update_area('seast');"
<!DOCTYPE html>
<html>
<script>
var time = '0'
var area = 'neast'
function update_area(input) {
area = input;
load_updated_image(area,time);
};
function update_time(input) {
time = input;
load_updated_image(area,time);
};
function load_updated_image(area,time) {
var url = 'http://personal.psu.edu/kps5442/modelimages/hrrr_'+area+'_wetbulb'+time+'.png';
document.getElementById("theImage").src = url;
document.getElementById("url").innerHTML = url;
};
</script>
<body onload="load_updated_image(area,time)">
<p>URL Output:</p>
<p id="url"></p>
<font size = 4><b>Forecast Hour: </b>
<font size = 3>
<a href="#" onmouseover="update_time(0);" /> 00</a>
<a href="#" onmouseover="update_time(1);" /> 01</a>
<a href="#" onmouseover="update_time(2);" /> 02</a>
<img id="theImage" src=undefined width="850" height="600" />
<br> <font size = 4><b>Region Selection: </b>
<a href="#" onclick="update_area('neast');" /> Northeast</a>
<a href="#" onclick="update_area('seast');" /> Southeast</a>
</body>
</html>
In JavaScript variables are not restricted to a single 'type', but a String will always be contained in quotes and a number will not. Also a variable cannot be, or start with, a number. This is why when you use a string as an argument it must be contained within quotes, otherwise it thinks you are sending a variable.

You're starting your document with <!doctype html> so you're saying you're writing HTML5, but there is a whole bunch of things that are incredibly wrong here due to use HTML3.2 and obsolete ways to invoke javascript.
Under modern HTML5 rules, there are no self-closing elements. It's not a hard error, but don't add that /> at the end of an <img.... Also <font> hasn't existed as element for 20 years now. It was removed in HTML4.1 in 1998. Then some semantics: if you need button functionality (i.e. clickable, but NOT navigating to some (part of a) page), use <button>. That's what it's for. Do not use <a>, and definitely not with href="#", because that's an active instruction for the browser to scroll to the top of the page. Finally, on...=... handlers are an ancient attribute that is unfortunately still supported, but you should never use. Use addEventListener in your Javascript, after you've declared all your HTML.
So let's just fix everything at the same time:
<!-- this line literally tells the browser "I am using HTML5" -->
<!DOCTYPE html>
<html>
<!-- always have a header section -->
<head>
<!-- no / at the end of meta elements -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>Always just fill this in, it's good practice</title>
<style>
/* you want this in its own file, see the note at the end of this post */
h1 {
font-size: 100%;
font-weight: bold;
}
</style>
</head>
<body>
<!-- sectioning isn't mandatory, but extremely good practice -->
<section id="output">
<h1>URL Output:</h1>
<p>Forecast Hour:</p>
<div class="controls">
<!-- let's use data attributes, and be explicit about the values here -->
<button class="forecast update" data-value="0">0h</button>
<button class="forecast update" data-value="1">1h</button>
<button class="forecast update" data-value="2">2h</button>
</p>
<!-- if you've never see the figure/figcaption elements: they exist -->
<figure id="forecast-image">
<!-- no / at the end of this element -->
<img src="placeholder.jpg" width="850" height="600" alt="forecast map">
<figcaption></figcaption>
</figure>
</section>
<section>
<h1>Region Selection</h1>
<div class="controls">
<button class="area update" data-value="neast">Northeast</buton>
<button class="area update" data-value="seast">Southeast<button>
</div>
</section>
<!-- don't put your script in the page. put it in its own file -->
<script src="updates.js"></script>
</body>
</html>
And then we make a second file for the javascript called updates.js:
// this goes last, so that the DOM is done by the time you invoke your script.
var currentTime = 0;
var currentArea = `NorthEast`;
// this function doesn't need parameters: we already know what they are
function load_updated_image() {
var url = `http://personal.psu.edu/kps5442/modelimages/hrrr_${currentArea}_wetbulb${currentTime}.png`;
let figure = document.getElementById(`forecast-image`);
// update the image
let img = figure.querySelector(`img`);
img.src = url;
// update the image caption with a link
let caption = figure.querySelector(`figcaption`);
caption.innerHTML = ``;
let link = document.createElement(`a`);
link.href = url;
caption.appendChild(link);
}
// update the area, and called image update
function update_area(area) {
currentArea = area;
load_updated_image();
};
// update the time, and called image update
function update_time(time) {
currentTime = timel
load_updated_image();
};
// add the initial page load handling
document.addEventListener(`ready`, evt => load_updated_image());
// add the click handling for forecast time buttons
let forecastButtons = document.querySelectorAll(`button.forecastupdate`);
forecastButtons.forEach(button => {
// get the button's data-value
value = button.dataset.value;
// and then set up a click listener to update the forecast time
button.addEventListener(`click`, evt => update_time(value));
});
// add the click handling for forecast area buttons
let areaButtons = document.querySelectorAll(`button.area.update`);
forecastButtons.forEach(button => {
// get the button's data-value
value = button.dataset.value;
// and then set up a click listener to update the forecast area
button.addEventListener(`click`, evt => update_area(value));
});
And then to be even more proper, don't use <style>...</style> but make a new file called "forecast.css" and then link to that in your page using <link href="forecast.css" rel="stylresheet"> (note: this is still HTML5, you don't put /> at the end. Link elements simply don't have a closing tag)

Is there way to use javascript to sychronize the server file with yours?

So that if i change a div with :
<form>
Datum: <input type="text" id="datum">
</form>
<div id='test1'>This is a dummy text</div>
<a id="www" >Replace it!</a>
<script>
var MyDiv1 = document.getElementById('datum');
document.getElementById("www").onclick = function() {
document.getElementById("test1").innerHTML = MyDiv1.value;
};
</script>
Is it possible to change it on the server right away instead of your local browser?
So not get reset with F5 Reload? And without using cookies?