In this post I’ll go over how you can utilize JQuery and CSS classes to show/hide various parts across the different sections of a page without creating a mess!
The Challenge
You’ve got a wizard-like page with multiple steps and you want to be able to show/hide various elements based upon the current step. Below is a dumbed-down example:
The colored boxes represent the parts that are being shared across the various sections of the page. For instance, the green box is being shared by the ‘Image Selection’ and ‘Order Confirmation’ sections. While the red box is being shared by all three sections.
So the challenge is: How do we show/hide these various parts across the sections of the page without making a mess? And by mess, I refer to duplicate code and/or little <% if..then %> snippets scattered throughout the page.
The Solution
By using some CSS/JQuery trickery, of course! What we’ll do is introduce some CSS classes that we will then apply to the various parts for which we need to handle visibility. Here are the classes that we will need:
- section – Represents a section
- requestor – Represents the requestor section
- image-selection – Represents the image selection section
- confirmation – Represents the order confirmation section
The CSS classes will then be applied to the various parts based upon the section inside which the part is to be shown:
<div>
<input type='hidden' id='section-to-show' />
<table>
<tr>
<td>Request Type:</td>
<td class='section requestor'>
<select>...</select>
</td>
<td class='section image-selection confirmation'>
<%= selectedRequestType %>
</td>
</tr>
...
<tr>
<td>First Name:</td>
<td><%= firstName %></td>
</tr>
<tr>
<td>Last Name:</td>
<td><%= lastName %></td>
</tr>
<tr class='section requestor confirmation'>
<td>Email</td>
<td><%= email %></td>
</tr>
...
...
<tr class='section image-selection confirmation'>
<td>Image</td>
<td class='section image-selection'>
Browse...
</td>
<td class='section confirmation'>
<img src='..' />
</td>
</tr>
...
</table>
</div>A few things to highlight:
– The hidden input field ‘section-to-show’ indicates the section to display. It’s value is set by the server-side code.
– There are two table columns inside the first table row. Only one will be visible based up the section that is being displayed.
– The first name and last name table rows don’t have any classes applied to them. This is because they are always visible.
– The last table row shown above gives an example of how you can make the visibility conditional for both the table row and the table column.
– I skipped various rows in the HTML form above to save some typing and to avoid being repetitive.
And now for the JQuery:
$(document).ready(function(){ // hide all sections to begin with $('.section').hide(); current_section = $('#section-to-show').val(); $("." + current_section).show(); });
And there you have it – a cleaner alternative to showing and hiding various parts across the sections of a page!
Dynamically creating input fields on tab via CoffeeScript and JQuery
inputId = 1; jQuery -> $("#fields :input").live 'keydown', (e) -> if isModifierKeyPressed e return if e.keyCode in [9, 13] e.preventDefault if isLastActivity($(this).attr 'id') addAnotherTextInput(); $(this).next().focus(); return false isModifierKeyPressed = (e) -> e.ctrlKey or e.altKey or e.shiftKey isLastActivity = (inputFieldId) -> inputNumber = (Number) inputFieldId.split('activity')[1] inputNumber == inputId addAnotherTextInput = -> inputId++ $("#fields").append getInputField inputId getInputField = (inputId) -> return "<input type='text' id='activity#{inputId}' class='input-super-large' placeholder='Type something and then press tab' />"
JQuery snippet to detect keystrokes on the numeric key-pad.
$(document).keydown(function (event) { toCharacter(event.keyCode); }); function toCharacter(keyCode) { // delta to convert num-pad key codes to QWERTY codes. var numPadToKeyPadDelta = 48; // if a numeric key on the num pad was pressed. if (keyCode >= 96 && keyCode <= 105) { keyCode = keyCode - numPadToKeyPadDelta; return String.fromCharCode(keyCode); } if (keyCode == 106) return "*"; if (keyCode == 107) return "+"; if (keyCode == 109) return "-"; if (keyCode == 110) return "."; if (keyCode == 111) return "/"; // the 'Enter' key was pressed if (keyCode == 13) return "="; //TODO: you should change this to interpret the 'Enter' key as needed by your app. return String.fromCharCode(keyCode); }
A little explanation is probably in order...
Javascript provides the
String.fromCharCode()
String.fromCharCode(65)