I'm trying to use PDF.js' viewer to display pdf files on a page.
I've gotten everything working, but I would like to be able to 'jump to' a specific page in the pdf. I know you can set the page with the url, but I would like to do this in javascript if it's possible.
I have noticed that there is a PDFJS object in the global scope, and it seems that I should be able to get access to things like page setting there, but it's a rather massive object. Anyone know how to do this?
You can set the page via JavaScript with:
var desiredPage = [the page you want];
PDFViewerApplication.page = desiredPage;
There is an event handler on this, and the UI will be adjusted accordingly. You may want to ensure this is not out of bounds:
function goToPage(desiredPage){
var numPages = PDFViewerApplication.pagesCount;
if((desiredPage > numPages) || (desiredPage < 1)){
return;
}
PDFViewerApplication.page = desiredPage;
}
In my case I was loading pdf file inside iframe so I had to do it in other way around.
function goToPage(desiredPage){
var frame_1 = window.frames["iframe-name"];
var frameObject = document.getElementById("iframe-id").contentWindow;
frameObject.PDFViewerApplication.page = desired page;
}
if Pdf shown into iframe and you want to navigate to page then use below code. 'docIfram' is iframe tag Id.
document.getElementById("docIframe").contentWindow.PDFViewerApplication.page=2
Related
I am building a website with several HTML pages, and going to fill up info on different pages through an API. I have added onclick listeners to HTML elements like this:
// ASSIGNING ELEMENTS AS VARIABLES
const EPL = document.getElementById('epl');
const bundesliga = document.getElementById('bundesliga');
const laliga = document.getElementById('laliga');
// ONCLICKS
EPL.onclick = function() {
getStandings('2021');
location.replace('standings.html');
}
bundesliga.onclick = function() {
getStandings('2088');
location.replace('standings.html');
}
laliga.onclick = function() {
getStandings('2224');
location.replace('standings.html');
}
When one of these is clicked, I call a function (getStandings) with its unique argument to fetch some data from the API. I also want to move to another HTML page, for which I used location.replace.
I'm caught in a dilemma: if I use the same JS file for every HTML page, when I get to the new HTML page, I get errors as the new HTML page does not have every element:
main.js:41 Uncaught TypeError: Cannot set property 'onclick' of null
But if I use different JS files, maybe one JS file for each HTML file, I cannot carry forward the bits of information I need. How can I get to the new HTML page, with its own JS file, without stopping and losing everything in the function I'm in currently, under the JS file of the old page? For example, the argument '2021' or '2088' are to be passed into the getStandings() function which will populate the new HTML page with data from an API. If I jump to a new HTML page with a new JS file, this is lost.
Is there a better way to organise my files? 😐😐😐😐😐
You can set your event listeners on the condition that the elements are not null e.g.
const EPL = document.getElementById('epl');
const bundesliga = document.getElementById('bundesliga');
const laliga = document.getElementById('laliga');
if(EPL){
EPL.onclick = function() {
getStandings('2021');
location.replace('standings.html');
}
}
etc...
Solved! As amn said, I can add URL parameters to the end of the URL of the new HTML page, then get the variables from its own URL once I'm on the new HTML page.
I think I would rather use classes instead of IDs to define the listener, and maybe IDs for dedicated action.
I have form with a Grid (telerik), i think the technology behind it doesnt matter. I let user click on a row in the grid. During the click I extract a value from the Grid with Javascript, like so:
function RadDrillDoubleClick(sender, eventArgs) {
var Code = eventArgs.getDataKeyValue("Status");
if (Code == "In Progress" || Code == "")
{
location.href = "Main1.aspx?mode=edit&DID=" + eventArgs.getDataKeyValue("D_ID");
}
else {
location.href = "Main1.aspx?mode=view&DID=" + eventArgs.getDataKeyValue("D_ID");
}
}
After user has clicked the grid, I call this JS function and send them to correct .aspx page with either VIEW or EDIT mode dependent directly on the Code.
What I'm trying to do is once I get to the Main1.aspx page, I want to be able to continue to hold the CODE value, because when users performs a certain action, I'll need to call a javascript function and use the actual CODE to determine what the user will be able to do.....
var Code = eventArgs.getDataKeyValue("Status");
is there any way I can somehow create like a GLOBAL Variable called
CodeValue
that I can pass around to another form without doing it in the URL?
When the browser navigates to a page, all current JavaScript is unloaded from the browser. This means any functions/variables, etc. will not be accessible on the new page unless you've persisted the value in some way.
Common ways of persisting the value include:
Add it to the query string of the URL the user is navigating to
Save the value to a cookie
Save the value to local/session storage
For your scenario, #1 is probably your best bet (keep in mind the user can have multiple browsers/tabs open to your site).
One way to get the value from URL is like this: on the page Main1.aspx, you add to your JavaScript a function that will run after page loads and that will get what it needs from the current URL
var globalValue; // variable that will receive the value from URL
window.onload = function() {
var thisURL = window.location.href;
globalValue = url.split("?").pop();
// this will store in globalValue everything that comes after the last "?"
// example: if the url is www.site.com/text?value, it will store string "value" to globalValue
};
is it possible to write a javascript to access the elements (knowing their id) in another open window? I want to refresh the page and read some elements' contents.
You can totally use sessionStorage ! Here is the Documentation
If user direct to next page in same tab, sessionStorage can easily save you data and reuse in next page.
// set in page A
window.sessionStorage.setItem('youdata', 'youdata');
// or window.sessionStorage['youdata'] = 'youdata';
// get in page B
var youdata = window.sessionStorage.getItem('youdata');
// or var youdata = window.sessionStorage['youdata'];
That's it! very simple!
If you'll open a new tab, you can use localStorage. Here Is the Documentation
The usage of localStorage is like the way of sessionStorage.
While do saving information for other pages, these two method only need browsers' support.
I am trying to make a basic Instagram web scraper, both art inspiration pictures and just generally trying to boost my knowledge and experience programming.
Currently the issue that I am having is that Casper/Phantomjs can't detect higher res images from the srcset, and I can't figure out a way around this. Instagram has their srcsets provide 640x640, 750x750, and 1080x1080 images. I would obviously like to retrieve the 1080, but it seems to be undetectable by any method I've tried so far. Setting the viewport larger does nothing, and I can't retrieve the entire source set through just getting the HTML and splitting it where I need it. And as far as I can tell, there is no other way to retrieve said image than to get it from this srcset.
Edit
As I was asked for more details, here I go. This is the code I used to get the attributes from the page:
function getImages() {
var scripts = document.querySelectorAll('._2di5p');
return Array.prototype.map.call(scripts, function (e) {
return e.getAttribute('src');
});
}
Then I do the standard:
casper.waitForSelector('div._4rbun', function() {
this.echo('...found selector ...try getting image srcs now...');
imagesArray = this.evaluate(getImages);
imagesArray.forEach(function (item) {
console.log(item);
However, all that is returned is the lowest resolution of the srcset. Using this url, for example, (https://www.instagram.com/p/BhWS4csAIPS/?taken-by=kasabianofficial) all that is returned is https://instagram.flcy1-1.fna.fbcdn.net/vp/b282bb23f82318697f0b9b85279ab32e/5B5CE6F2/t51.2885-15/s640x640/sh0.08/e35/29740443_908390472665088_4690461645690896384_n.jpg, which is the lowest resolution (640x640) image in the srcset. Ideally, I'd like to retrieve the https://instagram.flcy1-1.fna.fbcdn.net/vp/8d20f803e1cb06e394ac91383fd9a462/5B5C9093/t51.2885-15/e35/29740443_908390472665088_4690461645690896384_n.jpg which is the 1080x1080 image in the srcset. But I can't. There's no way to get that item as far as I can tell. It's completely hidden.
I found a way around it in Instagram's case. Instagram puts the source picture in a meta tag within the head. So, using the code I'll paste below, you can call all of the meta tags and then sort out which one is the source picture by checking if "og:image" is retrieved.
function getImages() {
var scripts = document.querySelectorAll('meta[content]');
return Array.prototype.map.call(scripts, function (e) {
return e.getAttribute('property') + " " + e.getAttribute('content');
});
}
And this is the way to sort the meta tags into only having the original image in its native resolution.
this.echo('...found selector ...try getting image srcs now...');
imagesArray = this.evaluate(getImages);
imagesArray.forEach(function (item) {
if (typeof item == "string" && item.indexOf('og:image') > -1) {
Edit: Unfortunately this only works for single image posts on Instagram (the site I'm trying to scrape) so this unfortunately does me no goo. The values within the meta tags don't change even if you load the next image in the post. I'm leaving this up though in case anyone else could use it, but it's not ideal for my own use case.
Yes indeed PhantomJS doesn't seem to support srcset, its Webkit engine is very old.
But to be fair, all the metadata related to the page is out in the open in the HTML as JSON in window._sharedData variable.
If you want to use a headless browser (and not parse it with any server-side language) you can do this:
var imgUrl = page.evaluate(function(){
return window._sharedData.entry_data.PostPage[0].graphql.shortcode_media.display_resources[2].src;
});
https://instagram.fhen2-1.fna.fbcdn.net/vp/8d20f803e1cb06e394ac91383fd9a462/5B5C9093/t51.2885-15/e35/29740443_908390472665088_4690461645690896384_n.jpg
Solution: So my solution was to use slimerjs. If I run the js file through "casperjs --engine=slimerjs fileName.js", I can retrieve srcsets in full. So if I say use this code:
function getImgSrc() {
var scripts = document.querySelectorAll("._2di5p");
return Array.prototype.map.call(scripts, function (e) {
return e.getAttribute("srcset");
});
}
on this url (https://www.instagram.com/p/BhWS4csAIPS/?taken-by=kasabianofficial) I will get (https://instagram.flcy1-1.fna.fbcdn.net/vp/b282bb23f82318697f0b9b85279ab32e/5B5CE6F2/t51.2885-15/s640x640/sh0.08/e35/29740443_908390472665088_4690461645690896384_n.jpg 640w,https://instagram.flcy1-1.fna.fbcdn.net/vp/b4eebf94247af02c63d20320f6535ab4/5B6258DF/t51.2885-15/s750x750/sh0.08/e35/29740443_908390472665088_4690461645690896384_n.jpg 750w,https://instagram.flcy1-1.fna.fbcdn.net/vp/8d20f803e1cb06e394ac91383fd9a462/5B5C9093/t51.2885-15/e35/29740443_908390472665088_4690461645690896384_n.jpg 1080w) as the result.
This is what I wanted as it means I can scrape those 1080 images. Sorry for this messy page, but I wanted to leave my trail of steps to any of those who might be trying like me.
No idea what I'm doing or why it isn't working. Clearly not using the right method and probably won't use the right language to explain the problem..
Photogallery... Trying to have a single html page... it has links to images... buttons on the page 'aim to' modify the path to the images by finding the name currently in the path and replacing it with the name of the gallery corresponding to the button the user clicked on...
example:
GALLERY2go : function(e) {
if(GalleryID!="landscapes")
{
var find = ''+ findGalleryID()+'';
var repl = "landscapes";
var page = document.body.innerHTML;
while (page.indexOf(find) >= 0) {
var i = page.indexOf(find);
var j = find.length;
page = page.substr(0,i) + repl + page.substr(i+j);
document.body.innerHTML = page;
var GalleryID = "landscapes";
}
}
},
There's a function higher up the page to get var find to take the value of var GalleryID:
var GalleryID = "portfolio";
function findGalleryID() {
return GalleryID
}
Clearly the first varGalleryID is global (t'was there to set a default value should I have been able to find a way of referring to it onLoad) and the one inside the function is cleared at the end of the function (I've read that much). But I don't know what any of this means.
The code, given its frailties or otherwise ridiculousness, actually does change all of the image links (and absolutely everything else called "portfolio") in the html page - hence "portfolio" becomes "landscapes"... the path to the images changes and they all update... As a JavaScript beginner I was pretty chuffed to see it worked. But you can't click on another gallery button because it's stuck in a loop of some sort. In fact, after you click the button you can't click on anything else and all of the rest of the JavaScript functionality is buggered. Perhaps I've introduced some kind of loop it never exits. If you click on portfolio when you're in portfolio you crash the browser! Anyway I'm well aware that 'my cobbled together solution' is not how it would be done by someone with any experience in writing code. They'd probably use something else with a different name that takes another lifetime to learn. I don't think I can use getElement by and refer to the class/id name and parse the filename [using lots of words I don't at all understand] because of the implications on the other parts of the script. I've tried using a div wrapper and code to launch a child html doc and that come in without disposing of the existing content or talking to the stylesheet. I'm bloody lost and don't even know where to start looking next.
The point is... And here's a plea... If any of you do reply, I fear you will reply without the making the assumption that you're talking to someone who really hasn't got a clue what AJAX and JQuery and PHP are... I have searched forums; I don't understand them. Please bear that in mind.
I'll take a stab at updating your function a bit. I recognize that a critique of the code as it stands probably won't help you solve your problem.
var currentGallery = 'landscape';
function ChangeGallery(name) {
var imgs = document.getElementsByTagName("img") // get all the img tags on the page
for (var i = 0; i < imgs.length; i++) { // loop through them
if (imgs[i].src.indexOf(currentGallery) >= 0) { // if this img tag's src contains the current gallery
imgs[i].src = imgs[i].src.replace(currentGallery, name);
}
}
currentGallery = name;
}
As to why I've done what I've done - you're correct in that the scope of the variables - whether the whole page, or only the given function, knows about it, is mixed in your given code. However, another potential problem is that if you replace everything in the html that says 'landscape' with 'portfolio', it could potentially change non-images. This code only finds images, and then replaces the src only if it contains the given keyword.