List of digital marketing companies in delhi ncr which provide prevent defaults of javascript

Advance Tutorial on Prevent Default In Javascript

1. Let's begin

That since we're on the topic of preventing default you know to you this might seem not super useful right now but this does become useful when you are starting to get into something like list of digital marketing companies in delhi ncr and a single page app where you might have a form submission and you don't want the page to actually refresh.

You just want to kind of grab that info out do something with that data and then you know not to have the page refresh. And so it's not aware of what a form looks like. No, I'm going to get rid of my link here and we'll put a form in here just so we can see it. So form a list of digital marketing companies in delhi ncr you have opening and closing tags. And not giving an ID because I do want to grab it out Id causes my form and forms will often have a method.

2.Tactics for better results

a. So if this one is method post that means we are posting the data to a server of some kind and we're not really going to do that. It's kind of beyond the scope of this lesson but let's see just observe what happens if we try to do that and we're doing input here and list of digital marketing companies in delhi ncr we'll do another input that is just a button actually button type he calls submit calls off the button and then within the button tags we can see Button submit.

b. So we won't see that in action. Let's see. And if we hit submit let's observe what happens. Submit. OK. It can't find the page that I want to do because normally you submit it your server will give you back a response that will give you a page to load for example. In this case, of course, we can't submit on gasping we're not allowed to do that. And it makes sense. Jeff's point is not really for that.

c. So let's say we don't want that to happen. And what I'm going to throw in a line break here what you can do using before. So the submit buttons underneath a little pet peeve of mine. So let's say we want to prevent that from happening. We don't want that page we don't want to get our error message. We just wanted to we want to grab that data and you know what.

d. Let's do a simple example let's say I want to grab the data and just append it to this list right here. And our callers are going kind of crazy. But let's say we want to append it to the list and list of digital marketing companies in delhi ncr not have the page actually refresh. Right and in the back and what you might do is if it was a single page up well you might say OK this is method post I'm going to grab that in my javascript. I will submit that to the server.

4.Response From the servers

a. Wait for a response and then do something. But again that's a bit beyond the scope. Will do a much simpler example. So let's say conc my form equals document talk get elements by id my form list of digital marketing companies in delhi ncr and my form we're going to add an event listener for submit events and let's give it a reference to a function that will define in a second here. To add to list is what I call it great function. Add to list. It's going to take in the event and first of all, you prevent default for saying why. Well, this could be named anything. I'm just choosing to call it we could call it event could call it anything really.

b. Let's try that again or refresh Now when are you to do submit and it doesn't actually do anything which is the behaviour I wanted right. I'm not getting that error message anymore. That error page and that was just built in functionality the default behaviour of form when you give it a method like a post. So let's say we do want to grab out the value of something and what we can do it's going to give this input an idea as well.

c. Call my input and at the time this function executes what we can do is we can say Konst my input equals document get element by id my input value is what we can get at this point. And if we want to see that console log my input seek a quick gander at it submit and there you see the input and you want to see something that's not jibberish. Let's try the name Bob for example right there. The value is changing based on whenever we hit submit. It just grabs out the input value. If we don't want value we can just see what it looks like what this object looks like.

6.Node and their Terms

a.Just out of curiosity and it it's just a node. And we can get the value of that node easily boom that value right. So we have the value. Now what I want to do is I want to be able to create a new list of digital marketing companies in delhi ncr item node element append the text into that ally and then take that ally and add it to my you out which I fortunately already grabbed out of the dorm years of consulate's items. Well OK. So therefore what I can do is I can say Konst new ally equals document Daut create elements the element I want to create is it. I now knew I thought inner text equals my input.

b. That should be working so far. Let's cancel all get out just again as a sanity check. We will refresh and let's try Phil for example. We have our node and we can now append our node to the list items very easily. So let's grab that constant which I did declare globally list items UL list items. Well and if you recall how can we append a child thought append child simple manipulation here to already.

c. That since we're on the topic of preventing default you know to you this might seem not super useful right now but this does become useful when you are starting to get into something like a single page app where you might have a form submission and you don't want the page to actually refresh. You just want to kind of grab that info out do something with that data and then you know not to have the page refresh. And so it's not aware of what a form looks like.

8.Link it through

a. I'm going to get rid of my link here and we'll put a form in here just so we can see it. So form you have opening and closing tags. And not giving an ID because I do want to grab it out Id causes my form and forms will often have a method. So if this one is method post that means we are posting the data to a server of some kind and we're not really going to do that.

b. It's kind of beyond the scope of this lesson but let's just observe what happens if we try to do that and we're doing input here and we'll do another input that is just a button actually button type he calls submit calls off the button and then within the button tags we can see Button submit.

c. So we won't see that in action. Let's see. And if we hit submit let's observe what happens. Submit. OK. It can't find the page that I want to do because normally you submit it your server will give you back a response that will give you a page to load for example. In this case, of course, we can't submit on gasping we're not allowed to do that. And it makes sense.

d. Jeff's point is not really for that. So let's say we don't want that to happen. And what I'm going to throw in a line break here what you can do using before. So the submit buttons underneath a little pet peeve of mine. So let's say we want to prevent that from happening. We don't want that page we don't want to get our error message.

9. Grab the data

We just wanted to we want to grab that data and you know what. Let's do a simple example let's say I want to grab the data and just append it to this list right here. And our callers are going kind of crazy. But let's say we want to append it to the list and not have the page actually refresh. Right and in the back and what you might do is if it was a single page up well you might say OK this is method post I'm going to grab that in my javascript.

I will submit that to the server. Wait for a response and then do something. But again that's a bit beyond the scope. Will do a much simpler example. So let's say conc my form equals document talk get elements by id my form and my form we're going to add an event listener for list of digital marketing companies in delhi ncr submit events and let's give it a reference to a function that will define in a second here. To add to list is what I call it great function.

Add to list. It's going to take in the event and first of all, you prevent default for saying why. Well, this could be named anything. I'm just choosing to call it we could call it event could call it anything really. Let's try that again or refresh Now when are you to do submit and it doesn't actually do anything which is the behaviour I wanted right. I'm not getting that error message anymore. That error page and that was just built in functionality the default behaviour of form when you give it a method like a post.

So let's say we do want to grab out the value of something and what we can do it's going to give this input an idea as well. Call my input and at the time this function executes what we can do is we can say Konst my input equals document get element by id my input value is what we can get at this point. And if we want to see that console log my input seek a quick gander at it submit and there you see the input and you want to see something that's not jibberish. Let's try the name Bob for example right there.

The value is changing based on whenever we hit submit. It just grabs out the input value. If we don't want value we can just see what it looks like what this object looks like. Just out of curiosity and it it's just a node.

Document Daut Element

And we can get the value of that node easily boom that value right. So we have the value. Now what I want to do is I want to be able to create a new list item node element append the text into that ally and then take that ally and add it to my you out which I fortunately already grabbed out of the dorm years of consulate's items. Well OK. So therefore what I can do is I can say Konst new ally equals document Daut create elements the element I want to create is it. I now knew I thought inner text equals my input.

That should be working so far. Let's cancel all get out just again as a sanity check. We will refresh and let's try Phil for example. We have our node and we can now append our node to the list items very easily. So let's grab that constant which I did declare globally list items UL list items. Well and if you recall how can we append a child thought append child simple manipulation here to already.