How can I suppress popup errors in javaScript? - javascript

I am working with an IBM product called Presto. It converts green screens to browser based pages. To do this it does strange things. I am dealing with text fields that randomly popup in different places. I am using the following code for each object to overcome:
document.getElementById("C0816").style.position = "absolute";
document.getElementById("C0816").style.left = "190px";
document.getElementById("C0816").style.top = "216px";
This has worked well until now. I am dealing with a page that will remove objects (text fields) & replace with different objects. This causes an error when it can't find the missing Id.
How can I suppress this error? I have tried several examples on this board but I am new to JavaScript & I am obviously placing it in the code wrong. Any help would be great, thank you.

Just check if the element exists before accessing properties.
const elem = document.getElementById("C0816");
if(elem) {
elem.style.position = 'absolute';
...
}

Related

Why do I get an Invalid Argument when using the removeLabel function in Google Script

I'd like to remove my user created label called "Add-to-Spendee-2", from a collection of emails. I've pretty much followed Google's removeLabel() Documentation to the dot on this, but I keep getting an "Invalid argument: label" error.
Here's the code:
function removeLabel()
{
var myLabel = GmailApp.getUserLabelByName('test-add-to-spendee-2');
var threads = GmailApp.search("label:test-add-to-spendee-2 AND from:swiggy AND subject:(Your receipt for Swiggy order)");
for (var x in threads)
{
var thread = threads[x]
thread.removeLabel(myLabel)
}
}
Note: If I substitute the removeLabel(myLabel) with any other function like markUnread(), the code works perfectly.
I think your code will work but I think all you need to do is:
var lbl=GmailApp.getUserLabelByName('Q0/Subject/Name');
var threads=GmailApp.search('label:Q0/Subject/Name');//exactly as you created it
lbl.removeFromThreads(threads);
Try using the debugger and make sure that threads is getting an array of GmailThread objects.
This is what the label look like in the Gmail search window:
They changed the slashes to dashes and used lower case and that's not really what the label looks like.
As I said above in my comment:
I just did that recently and I found that the description of the label in the gmail search window did not agree with how I actually created the label. It displayed a label like this q0-subject-name and I had it created as Q0/Subject/Name when I used q0-subject-name I couldn't find the label and when I used Q0/Subject/Name I found it.

Can't access object in jquery (prevObject?)

A function in my WP plugin has just randomly (as far as I can tell) stopped working.
Here's the code in question:
window.send_to_editor = function(html) {
var classes = jQuery('img',html).attr('class');
var items = classes.split(" ");
... more stuff here
}
I've confirmed that the html variable is indeed an img html tag. Here's what firebug shows when I do a console.log of the object (console.log(jQuery('img',html));):
Object[]
context -> undefined
jquery -> "1.11.2"
length -> 0
prevObject -> Object[img.alignnone.size-full.wp-image-1234 name.jpg]
And the error it shows is classes is undefined.
I figure there's something wrong with the object I get, but this used to work recently and I'm not aware of any changes in the site that could have caused this.
I'd appreciate any input on this.
EDIT:
More info. This happens with two plugins which are supposed to be unrelated (made by different people). It happens when, after uploading an image to the server (or selecting a previously uploaded picture) you try to insert it into the post.
As I said before this error has appeared out of nowhere, it was working as intended a couple days ago. The only thing I can think of that has changed since then is the domain name, but I can't see how that could be related.
The jQuery selector always returns a jQuery object, but when the length is 0 then no elements were found matching the selector that you provided. In your example you've confirmed that nothing is selected as the length of the jQuery object is 0. Perform a check whether an element was selected like this:
var $els = jQuery('img',html),
classes;
if ($els.length) {
classes = $els.attr("class");
}
Keep in mind that your DOM query is limited by what you pass in as the html parameter. If you simply want to find the images on the page do: var $els = jQuery('img');
I finally managed to fix this; the key was parsing the html string variable into proper HTML, using jQuery.parseHTML(). Thanks to everyone who helped!

Bokeh: App Not Visualizing--Requirements? (extra_generated_classes, jsmodel)

I'm new to Bokeh, and am trying to create a web-app. I'm having issues where when I run the server, and navigate to the specified web URL, nothing shows beyond a small "link to this" in the upper left hand corner. For reference, I'm using python 2.7, via Anaconda, on Windows7.
I first created a simple example, modeled off of the stock applet. I noticed that in the class Dashboard(VBox), there were, in addition, declarations of extra_generated_classes, and jsmodel. When I omitted these two lines, nothing would show.
I read through some of the bokeh code, but I'm still not quite understanding what the two lines do, and how to set them properly. In my new example, my formatting looks like this
self.children = [self.filterrow, self.lineplot1]
self.filterrow.children = [self.filter_box, self.input_box]
self.filter_box.children = [self.ticker_select, self.date_select]
self.input_box.children = [self.value_select, self.value1_select]
where
lineplot1 = Instance(Plot)
filterrow = Instance(HBox)
ticker_select = Instance(Select)
date_select = Instance(Select)
value = String(default = '')
value1 = String(default = '')
and in my def create(cls)
obj = cls()
obj.filterrow = HBox()
obj.filter_box = VBoxForm()
obj.input_box = VBoxForm()
I've compared my working applet side by side with my non-showing applet, and can't find any significant format differences. Learning by replications, I have
class Dashboard(VBox):
extra_generated_classes = [["Dashboard", "Dashboard", "VBox"]]
jsmodel = "VBox"
in the non-functioning code. Is this correct? How should these two lines be set? Do I need both? Am I missing something? After repeated examination and comparison of the code, I still don't understand why one visualizes properly and the other doesn't.
If this isn't the issue, what is the best way for me to debug the visualization portion of the applet? Any assistance would be greatly appreciated. Thanks!

Adding Javascript variables to HTML elements

So, I have some code that should do four things:
remove the ".mp4" extension from every title
change my video category
put the same description in all of the videos
put the same keywords in all of the videos
Note: All of this would be done on the YouTube upload page. I'm using Greasemonkey in Mozilla Firefox.
I wrote this, but my question is: how do I change the HTML title in the actual HTML page to the new title (which is a Javascript variable)?
This is my code:
function remove_mp4()
{
var title = document.getElementsByName("title").value;
var new_title = title.replace(title.match(".mp4"), "");
}
function add_description()
{
var description = document.getElementsByName("description").value;
var new_description = "Subscribe."
}
function add_keywords()
{
var keywords = document.getElementsByName("keywords").value;
var new_keywords = prompt("Enter keywords.", "");
}
function change_category()
{
var category = document.getElementsByName("category").value;
var new_category = "<option value="27">Education</option>"
}
remove_mp4();
add_description();
add_keywords();
change_category();
Note: If you see any mistakes in the JavaScript code, please let me know.
Note 2: If you wonder why I stored the current HTML values in variables, that's because I think I will have to use them in order to replace HTML values (I may be wrong).
A lot of things have been covered already, but still i would like to remind you that if you are looking for cross browser compatibility innerHTML won't be enough, as you may need innerText too or textContent to tackle some old versions of IE or even using some other way to modify the content of an element.
As a side note innerHTML is considered from a great majority of people as deprecated though some others still use it. (i'm not here to debate about is it good or not to use it but this is just a little remark for you to checkabout)
Regarding remarks, i would suggest minimizing the number of functions you create by creating some more generic versions for editing or adding purposes, eg you could do the following :
/*
* #param $affectedElements the collection of elements to be changed
* #param $attribute here means the attribute to be added to each of those elements
* #param $attributeValue the value of that attribute
*/
function add($affectedElements, $attribute, $attributeValue){
for(int i=0; i<$affectedElements.length; i++){
($affectedElements[i]).setAttribute($attribute, $attributeValue);
}
}
If you use a global function to do the work for you, not only your coce is gonna be easier to maintain but also you'll avoid fetching for elements in the DOM many many times, which will considerably make your script run faster. For example, in your previous code you fetch the DOM for a set of specific elements before you can add a value to them, in other words everytime your function is executed you'll have to go through the whole DOM to retrieve your elements, while if you just fetch your elements once then store in a var and just pass them to a function that's focusing on adding or changing only, you're clearly avoiding some repetitive tasks to be done.
Concerning the last function i think code is still incomplete, but i would suggest you use the built in methods for manipulating HTMLOption stuff, if i remember well, using plain JavaScript you'll find yourself typing this :
var category = document.getElem.... . options[put-index-here];
//JavaScript also lets you create <option> elements with the Option() constructor
Anyway, my point is that you would better use JavaScript's available methods to do the work instead of relying on innerHTML fpr anything you may need, i know innerHTML is the simplest and fastest way to get your work done, but if i can say it's like if you built a whole HTML page using and tags only instead of using various semantic tags that would help make everything clearer.
As a last point for future use, if you're interested by jQuery, this will give you a different way to manipulate your DOM through CSS selectors in a much more advanced way than plain JavaScript can do.
you can check out this link too :
replacement for innerHTML
I assume that your question is only about the title changing, and not about the rest; also, I assume you mean changing all elements in the document that have "title" as name attribute, and not the document title.
In that case, you could indeed use document.getElementsByName("title").
To handle the name="title" elements, you could do:
titleElems=document.getElementsByName("title");
for(i=0;i<titleElems.length;i++){
titleInner=titleElems[i].innerHTML;
titleElems[i].innerHTML=titleInner.replace(titleInner.match(".mp4"), "");
}
For the name="description" element, use this: (assuming there's only one name="description" element on the page, or you want the first one)
document.getElementsByName("description")[0].value="Subscribe.";
I wasn't really sure about the keywords (I haven't got a YouTube page in front of me right now), so this assumes it's a text field/area just like the description:
document.getElementsByName("keywords")[0].value=prompt("Please enter keywords:","");
Again, based on your question which just sets the .value of the category thingy:
document.getElementsByName("description")[0].value="<option value='27'>Education</option>";
At the last one, though, note that I changed the "27" into '27': you can't put double quotes inside a double-quoted string assuming they're handled just like any other character :)
Did this help a little more? :)
Sry, but your question is not quite clear. What exactly is your HTML title that you are referring to?
If it's an element that you wish to modify, use this :
element.setAttribute('title', 'new-title-here');
If you want to modify the window title (shown in the browser tab), you can do the following :
document.title = "the new title";
You've reading elements from .value property, so you should write back it too:
document.getElementsByName("title").value = new_title
If you are refering to changing text content in an element called title try using innerHTML
var title = document.getElementsByName("title").value;
document.getElementsByName("title").innerHTML = title.replace(title.match(".mp4"), "");
source: https://developer.mozilla.org/en-US/docs/DOM/element.innerHTML
The <title> element is an invisible one, it is only displayed indirectly - in the window or tab title. This means that you want to change whatever is displayed in the window/tab title and not the HTML code itself. You can do this by changing the document.title property:
function remove_mp4()
{
document.title = document.title.replace(title.match(".mp4"), "");
}

JS 1-2k variables make page load slow

On one page of my website the user has the ability to choose and remove up to 2000 items through selecting multiple string representations of them in a dropdown list.
On page load, the objects are loaded onto the page from a previous session into 7 different drop-down lists.
In the window.onload event, the function looping through the items in the drop-downs makes an internal collection of the objects by adding them to a global array - This makes the page ridiculously slow to load, so, I'm fairly certain probably doing it wrong!
How else am I supposed to store these variables?
This is their internal representation:
function Permission(PName, DCID, ID) {
this.PName = PName;
this.DCID = DCID;
this.ID = ID;
}
where: PName is string. DCID is int. ID is int.
EDIT:
Thanks for the quick replies! I appreciate the help, I'm not great with JS! Here is more information:
'selectChangeEvent' is added to the Change and Click event of the Drop down list.
function selectChangeEvent(e) {
//...
addListItem(id);
//...
}
'addListItem(id)' sets up the visual representation of the objects and then calls :
function addListObject(x, idOfCaller) {
var arIDOfCaller = idOfCaller.toString().split('-');
if (arIDOfCaller[0] == "selLocs") {
var loc = new AccessLocation(x, arIDOfCaller[1]);
arrayLocations[GlobalIndexLocations] = loc;
GlobalIndexLocations++;
totalLocations++;
}
else {
var perm = new Permission(x, arIDOfCaller[1], arIDOfCaller[2]);
arrayPermissions[GlobalIndexPermissions] = perm;
GlobalIndexPermissions++;
totalPermissions++;
}
}
Still not enough to go on, but there are some small improvements I can see.
Instead of this pattern:
var loc = new AccessLocation(x, arIDOfCaller[1]);
arrayLocations[GlobalIndexLocations] = loc;
GlobalIndexLocations++;
totalLocations++;
which seems to involve redundant counters and has surplus assignment operations, try:
arrayLocations[arrayLocations.length] = new AccessLocation(x, arIDOfCaller[1]);
and just use arrayLocations.length where you would refer to GlobalIndexLocations or totalLocations (which fromt he code above would seem to always be the same value).
That should gain you a little boost, but this is not your main problem. I suggest you add some debugging Date objects to work out where the bottleneck is.
You may want to consider a design change to support the load. Some sort of paged result set or similar, to cut down on the number of concurrent records being modified.
As much as we desperately want them to be, browsers aren't quite there yet in terms of script execution speed that allow us to do certain types of heavy lifting on the client.
While I haven't tested this idea, I figured I'd throw it out there - might it be faster to return a JSON string from the server side, where your array is fully calculated on that side?
From that point, I'd wager that eval()'ing it (as evil as this may be) might be fast enough to where you could then write the contents onto the page, and your array setup would already be taken care of.
Then again, I suppose the amount of work it'd take the browser to construct the 2k new objects and inject them into the DOM wouldn't necessarily help the speed side of things in the end. At the end of the day, a design change is probably necessary, but sometimes we're stuck with what we've got, eh?

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