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168 lines
3.4 KiB
168 lines
3.4 KiB
# DOM Input
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### LESSON OBJECTIVES
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_after this lesson, students will be able to:_
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1. Capture text input from the browser
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1. Use a form's submit event
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1. Build a list from input
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## Capture text input from the browser
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Provide a means for the user to provide input, and capture that input with an event handler.
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Make an input field and a button in index.html
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```javascript
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<input type="text" id="input-box" />
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<input type="submit" id="submit-btn" />
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```
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Set an event on the submit
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```javascript
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$('#submit-btn').on('click', () => {
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console.log('clicked');
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});
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```
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Make it so the handler grabs the value inside the input box (and logs it to check)
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Use jQuery `.val()`
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```javascript
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$('#input-box').val()
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```
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```javascript
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$('#submit-btn').on('click', () => {
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console.log('clicked');
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console.log( $('#input-box').val() );
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});
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```
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## Use a form's submit event
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With a **form** tag you can hit the enter key to submit the form data.
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```javascript
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<form>
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<input type="text" placeholder="enter your name" id="input-box"/>
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<input type="submit">SUBMIT</button>
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</form>
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```
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Set the handler on the form element instead of the submit.
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```javascript
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$('form').on('submit', () => {
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console.log('clicked');
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console.log( $('#input-box').val() );
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});
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```
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### Prevent default refresh
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When you submit the form, the default action is to refresh the page. Let's prevent this default behavior using the freebie `event`.
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```javascript
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$('form').on('submit', (event) => {
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console.log('clicked');
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console.log( $('#input-box').val() );
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event.preventDefault();
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});
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```
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### Reset your input field
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`.trigger()` can trigger events on elements (click, hover, etc). The `reset` event clears a text input
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```javascript
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$(elem).trigger('reset');
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```
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```javascript
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$('form').on('submit', (event) => {
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console.log('clicked');
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console.log( $('#input-box').val() );
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event.preventDefault();
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$(event.currentTarget).trigger('reset');
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});
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```
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## Build a list from input
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Make a nonsense list to store any kind of nonsense
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* Make a `list` array where nonsense data will be stored
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* Push input into the list
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* Run a function **render** that will render items in the list.
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```javascript
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const list = [];
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$('form').on('submit', (event) => {
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console.log('clicked');
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console.log( $('#input-box').val() );
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list.push( $('#input-box').val() );
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event.preventDefault();
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$(event.currentTarget).trigger('reset');
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render();
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});
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```
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* Make **render** function to iterate over all items in the list
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```javascript
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const render = () => {
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console.log('render everything in the list');
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console.log('list: ', list);
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list.forEach((item) => {
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console.log(item);
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});
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}
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```
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* Let's build in some `ul`s for the list items
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```html
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<ul></ul>
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```
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* Make a list item for every item in the array
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```javascript
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const render = () => {
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console.log('render everything in the list');
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console.log('list: ', list);
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$('ul').empty();
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list.forEach((item) => {
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$('ul').append('<li>' + item + '</li>');
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});
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}
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```
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* Add an event listener to each item that calls on one single event handler
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```javascript
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list.forEach((item) => {
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const $li = $('<li>' + item + '</li>');
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$li.on('click', doNonsense);
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$('ul').append($li);
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});
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```
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```javascript
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const doNonsense = (event) => {
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console.log('item clicked: ', event.currentTarget);
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$(event.currentTarget).css('background-color', 'red');
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}
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```
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