So, I've tried several times to thrust myself into the world of website development. Each time, I have abandoned a project for one simple reason: lists.
I would like to know, from front to back, the dataflow for a system which follows the following sequence of events:
The user is shown a list in a website
The user fills out a new list item in some sort of modal dialog
The user hits "Submit" and that item is now added to the list.
That new list item is sent to the server to be stored
Would there be a whole new page load? When would the data be posted to the server? What are the various options for this (seemingly simple) application? I am targeting relatively small web tools. Not necessarily single page, but I'm not against it.
I understand how to add the new <li> to a list with JQuery, and I know how to build the modal with HTML. I can pull the data from the modal, but I'm not sure how to take that data from JQuery, turn it into the appropriate block of HTML (which could be rather complex), and store the new record in the database.
I can't seem to find a tutorial on this sort of data handling.
Thank you!
Simple. Since you mentioned jQuery, let's use jQuery. Ready? Here we go!
I'm assuming you have a textarea or an input in your modal where a user can enter text. If so, give it an id attribute so it can be referenced, like id="myText".
Then, to take the textarea or input's content and turn it into a list item in your list, you'll need to append an <li> with the textarea's content to its parent <ul> tag. Again, you'll need some way to reference the <ul> tag, so give the <ul> tag an id attribute, something like myList, so it becomes <ul id="myList">.
Now, it's just a matter of taking the val()ue from the input field, and appending it to the list. This is how you do that.
var textareaStuff = $('#myText').val();
$('#myList').append('<li>'+textareaStuff+'</li>');
That wasn't so hard, was it? This is actually quite fun.
I will admit, POSTing stuff to the server may take some getting used to, but it's not too hard.
I've prepared an HTML file for you that does all these things, with pretty detailed documentation. It should be able to help you learn what you're wanting to learn. It's below.
<!DOCTYPE html>
<html>
<head>
<title>My jQuery Experiments</title>
</head>
<body>
<!-- Here's your list with its ID so we can reference it in JS. -->
<ul id="myList">
<li>Sample Item 1</li>
</ul>
<input id="myText"> <!-- Here's your input field. This can be in a modal. -->
<button id="addItemButton">Add Item</button> <!-- We need a save button. -->
<!-- Include jQuery -->
<script type="text/javascript"
src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
<!-- This is the javascript you'll need to write and understand -->
<script type="text/javascript" >
// When the element with id="addItemButton" is clicked,
$('#addItemButton').click(function() {
// Append the stuff in brackets to the element with id="myList"
$('#myList').append('<li>' + $('#myText').val() + '</li>');
// ^ The stuff in brackets is an li code with the value of the HTML
// element with id="myText", your input field above.
// Now to post it to a server, we'll need to use AJAX.
// Luckily, jQuery has an AJAX function. It looks like this:
$.ajax('http://example.com/mysaver.php', {
// We're POSTing stuff to the server.
method: 'post',
// This is the data to send to the server.
// It is a JSON object.
// If using PHP, you'll get $_POST['item'] = whatever is in id="myText"
data: { item: $('#myText').val() },
// If the AJAX request was successful,
success: function(data) {
// The argument 'data' contains whatever the server returned.
},
// If not,
error: function(jqXHR) {
// Handle your error here.
}
});
});
</script>
</body>
</html>
I hope this was helpful! Go ahead and approve this answer if it was, and please feel free to ask further questions in the comments and I'll do my best to help out where I can.
Related
I'm trying to create a custom element for reuse. What I have is data consisting of three attributes that will be displayed on it's respective page, depending on the link you click.
I'm using the Polymer Starter Kit. Basically, I want to have a page of information that changes depending on what the URL is. I have a list of programs on a page with links to their respective pages. So far I have this:
In my index.html, I have a section that looks like this:
<section data-route="programs">
<paper-material elevation="1">
<h1>Programs</h1>
<a href$="{{baseUrl}}programs/firstprogram">Program 1</a></br>
<a href$="{{baseUrl}}programs/secondprogram">Program 2</a></br>
<a href$="{{baseUrl}}programs/thirdprogram">Program 3</a></br>
</paper-material>
</section>
Then I have a custom element, program-info, that looks like this
<dom-module id="program-info">
<template>
<h2 class="page-title">{{program.name}}</h2>
<p>{{program.price}}</p>
<p>{{program.description}}</p>
</template>
<script>
(function() {
'use strict';
Polymer({
is: 'program-info'
});
})();
</script>
</dom-module>
Based on the program that was clicked, I want to grab data and use it in my custom element (name, price, description). I've thought about putting it in an array since there are only seven programs, but I don't know understand how to grab the right item in the array based on the URL.
Any thoughts?
If you are indeed using PSK, take a look at the section/page user-info in app/index.html. It displays information about a user based the name that was grabbed from the URL.
Of course you should also take a look at the routing configuration in app/elements/routing.html to figure out how the name is grabbed from the URL and set to the params variable.
Then you should add/modify your programs route to suit your needs.
Edit:
You can see a similar approach in this sample app : The data is fetch when the route changes and is then set to an article property in the scope of the blog-app element. In this element, said article property is itself bound to the similarly named property of the "page element" article-detail that is in charge of displaying the article's content that was previously fetched over the network.
I have an app that requires HTML to be pieced together from different APIs. Rather than getting into specifics there, let me just say that we have tried getting away from that many times but in the end the best answer always end up being what we currently have. Hopefully that changes someday but for now it's working great.
Currently, the HTML is parsed together as a string server-side using NodeJS and sent across the wire as complete HTML to be rendered. I'm in the process of adopting AngularJS, and while I'm loving it I am stuck on this issue-- how can I use Angular templating to insert invalid HTML at times?
The server will return three JSON fields: leadingHTML, trailingHTML, and copy. The copy field is always valid HTML, but leadingHTML and trailingHTML can sometimes return invalid HTML. When all three are added together, valid HTML results.
Let me illustrate:
leadingHTML='<figure>';
copy = '<img src="img1.jpg"/><img src="im2.jpg"/><figcaption>I love AngularJS</figcaption>';
trailingHTML='</figure>';
As you can see, if you add those together you will get the valid HTML that is required to be displayed. It's pretty easy to make the fields trustworthy HTML in Angular:
for (i in data.results){
data.results[i].copy=$sce.trustAsHtml(data.results[i].copy);
data.results[i].leadingHTML =$sce.trustAsHtml(data.results[i].leadingHTML );
data.results[i].trailingHTML =$sce.trustAsHtml(data.results[i].trailingHTML );
}
And then render the copy in my view:
<div ng-repeat='i in data.result'>
<p ng-bind-html='i.copy'></p>
</div>
But I need a way that does what this looks like it would do, but the leadingHTML and trailingHTML scope variables get render as strings:
<div ng-repeat='i in data.result'>
{{ i.leadingHTML }}
<p ng-bind-html='i.copy'></p>
{{ i.trailingHTML }}
</div>
Is the best answer here to build the template via javascript? Would that even work?
Are you able to pre-process your data so that you do have valid HTML?
var item;
for (i in data.results){
item = data.results[i];
item.content = $sce.trustAsHtml(item.leadingHTML + item.copy + item.trailingHTML);
}
Then you can just bind to the combined content in the view:
<div ng-repeat='i in data.results'>
<div ng-bind-html='i.content'></div>
</div>
Edit:
Yes, this will allow you to embed expressions in your HTML content.
In fact, you will need to be careful that you aren't opening yourself up to security exploits in the trusted HTML content (see the example at the bottom of the page for the $sce service).
Using $sce.trustAsHtml in this way is roughly equivalent to loading a directive's templateUrl from your site, so the security considerations around that are probably the same. See the "How does it work?" and
"Impact on loading templates".
I have situations where I need to prepend an item to a list that is initially generated using ng-repeat. How do I do this?
<div ng-click="prependItem()>Click Here</div>
<div ng-repeat="item in items">
<div class="someClass">Item name: {{item.name}}</div>
<div class="anotherClass">Item type: {{item.type}}</div>
</div>
If I click on prependItem() I want want the new item to be added to the top of the list. Obviously, I don't want to regenerate the entire ng-repeat. I've been unable to find any documentation that would explain how to do this. Thank ahead of time for any help!
scope.prependItem = function (newItem) {
items.unshift(newItem);
};
AngularJS is smart enough to know the addition, and only create html element for it
http://plnkr.co/edit/qzIfzSP6buiQ49rDreNk?p=preview
You can see from console that only the newly added item will log messages
ng-repeat will rebuild the list if you add an item to the front of your array. If you add it to the end it's smarter in that it will only update the DOM to reflect the change for the one item you've added in.
Because you've added an item to the front, it has to move everything in the DOM so I think it just rebuilds it as it's easier to do than moving (don't quote me on that though lol). It isn't necessarily a bad thing to rebuild that list (unless it's huge, you won't even notice the refresh, if it is very big, I'd recommend showing a spinner whilst it rebuilds the html, that's the approach we've taken at work; since the user has clicked the button they're expecting the interaction so the spinner seemed like the best compromise whilst angular rerendered).
I'm trying to figure out how to link an html picture element back to the database entry that was originally used to generate the picture link.
I am using Meteor:
- I have a database that contains photosets data from Flickr API
- In the HTML, I have a handlebar "each" script that iterates through each photoset in the database and then uses this info to generate the html for the photoset cover picture links.
- When the html renders, the photoset cover pictures are downloaded from Flickr and displayed to the screen.
I would like to be able to click on the photoset cover picture and then automatically generate the links to the pictures in the photoset. But I don't understand how to dynamically link the html picture elements back to their respective database entries that were originally used for generating the picture links. I need to be able to find the original database entries so that I can load the info needed for generation of subsequent links.
As a newb to all of this I'm not really sure where to start looking or what to try. I've wondered about creating an object with custom key pairs to 'memorise' the identity of each photoset picture. Is this the way to go, or is there an easier way that I am overlooking?
Thanks.
Say you have your pictures being put out this way:
Template.mytemplate.helpers({
picture:function() {
return pictures.find()
}
});
You can also do this instead, which is pretty much the same thing:
Template.mytemplate.picture = function() {
return pictures.find();
}
With the html
<template name="pictures">
{{#each picture}}
<img src="{{src}}" class="pictureselector"/>
{{/each}}
</template>
You can use events which can get data from that particular picture document/record
Template.mytemplate.events({
'click .pictureselector':function(event,template) {
console.log(this._id); //Should give you the `_id` of the picture that was clicked
}
});
this is the data context of the element that was clicked & generate the link you want using the data inside this.
Be careful if you use something with a callback inside the click like Meteor.call, you will have to relay the message down via var self = this otherwise the context of this would become the one of Meteor.call
Ok, I am playing around with Backbone, node.js, Underscore, Backbone Boilerplate so I have enough knowledge. Been asking questions like crazy as I still can't quite get my head around it. I am currently attempting to use the Underscore library with Backbone Boilerplate to make a very simple template which will allow me to pass in data; then when the model is updated, change the view which would change the template. I believe this is the correct way of doing it, instead of writing HTML code inside my JS file? Stop me if I'm wrong.
The Backbone Boilerplate has its template .fetch() system which I understand. However it would mean writing HTML in my JS I believe. So I wanted to use Underscore to simply pass information from the model to the view to the modules to render the template again (or I might be able to skip the view completely?).
My question is why won't this work, I think it's because I'm not changing it to JSON.
My HTML template:
<div>
<script id="rtemp" type="text/x-underscore-template">
<span><%= title %></span>
</script>
</div>
And the JavaScript:
define([
// Global application context.
"app",
// Third-party libraries.
"backbone",
"underscore",
"json2"
],
function(app, Backbone) {
var Attempt = app.module();
Attempt.Model = Backbone.Model.extend({});
Attempt.Collection = Backbone.Model.extend({});
Attempt.Views.Tutorial = Backbone.View.extend ({
template: "app/templates/attempt",
render: function(done) {
var tmpl = app.fetchTemplate(this.template);
//console.info(tmpl);
this.$el.html(tmpl({title: 'This is a title'}))
}
});
return Attempt;
});
When I inspect the element it shows in the <div> however it still has the template script tags around it so doesn't show on the page in HTML. I tried using json2 to convert it to JSON first, but that didn't seem to work unless I did something wrong. Is Underscore the best thing to use? I assumed so as it's a Backbone dependency. Or should I use something else. I just want to avoid writing HTML in my JS.
If I understand you right, you're ending up with this HTML:
<div>
<script id="rtemp" type="text/x-underscore-template">
<span>This is a title</span>
</script>
</div>
That's the right behavior based on the code you're using but that's clearly not the result you want.
The <script> wrapper for templates is used when you're embedding the template inside an HTML page. This is done so that the browser won't try to interpret your template as HTML and to keep the browser from trying to render it on its own. In such cases, you'd have the template embedded in the HTML page like this:
<!-- Some HTML stuff... -->
<script id="rtemp" type="text/x-underscore-template">
<span><%= title %></span>
</script>
<!-- Some other HTML stuff... -->
and you'd use it like this:
var t = _.template($('#rtemp').html());
var html = t(...)
The $('#rtemp').html() part extracts just the content of the template's <script> wrapper so _.template would only see <span><%= title %></span> and the final processed template would just be a simple <span>. For example: http://jsfiddle.net/ambiguous/dzPzC/
In your case, you're reading the entire <div><script>...</script></div> as the template and feeding that to _.template. The result is that tmpl({title: 'This is a title'}) still includes the <script>, the browser doesn't know what to do with a <script type="text/x-underscore-template"> so the <span> that you're interested in doesn't get rendered at all.
You don't need the <script> wrapper at all, that's only needed when you're embedding a raw template inside some HTML. Your template only needs the the content of your <script>:
<span><%= title %></span>
Demo: http://jsfiddle.net/ambiguous/QuwSX/
The argument that you're passing to the template function:
tmpl({ title: '...' })
is fine, the compiled template function just wants to see a JavaScript object. People talk about passing it JSON and often use the toJSON method to prepare data for the template but that's an abuse of terminology; the template really wants an object and JSON is, technically, a string.