1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>Code Igniter User Guide</title>
<style type='text/css' media='all'>@import url('../userguide.css');</style>
<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
<script type="text/javascript" src="../scripts/nav.js"></script>
<script type="text/javascript" src="../scripts/prototype.lite.js"></script>
<script type="text/javascript" src="../scripts/moo.fx.js"></script>
<script type="text/javascript">
window.onload = function() {
myHeight = new fx.Height('nav', {duration: 400});
myHeight.hide();
}
</script>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv='expires' content='-1' />
<meta http-equiv= 'pragma' content='no-cache' />
<meta name='robots' content='all' />
<meta name='author' content='Rick Ellis' />
<meta name='description' content='Code Igniter User Guide' />
</head>
<body>
<!-- START NAVIGATION -->
<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle.jpg" width="153" height="44" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
<div id="masthead">
<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
<tr>
<td><h1>Code Igniter User Guide Version 1.4.0</h1></td>
<td id="breadcrumb_right"><a href="../toc.html">Full Table of Contents</a></td>
</tr>
</table>
</div>
<!-- END NAVIGATION -->
<!-- START BREADCRUMB -->
<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
<tr>
<td id="breadcrumb">
<a href="http://www.codeigniter.com/">Code Igniter Home</a> ›
<a href="../index.html">User Guide Home</a> ›
Helper Functions
</td>
<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="www.codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td>
</tr>
</table>
<!-- END BREADCRUMB -->
<br clear="all" />
<!-- START CONTENT -->
<div id="content">
<h1>Helper Functions</h1>
<p>Helpers, as the name suggests, help you with tasks. Each helper file is simply a collection of functions in a particular
category. There are <dfn>URL Helpers</dfn>, that assist in creating links, there are <dfn>Form Helpers</dfn>
that help you create form elements, <dfn>Text Helpers</dfn> perform various text formatting routines,
<dfn>Cookie Helpers</dfn> set and read cookies, <dfn>File Helpers</dfn> help you deal with files, etc.
</p>
<p>Unlike most other systems in Code Igniter, Helpers are not written in an Object Oriented format. They are simple, procedural functions.
Each helper function performs one specific task, with no dependence on other functions.</p>
<p>Helpers are intentionally kept very simple so that they can be used within your <strong>View Files</strong> with a minimal amount of code.
This is important if you intend to have designers or non-programmer will be working with your view files, since it keeps the code to a minimum.
</p>
<p>Code Igniter does not load Helper Files by default, so the first step in using
a Helper is to load it. Once loaded, it becomes globally available in your <a href="../general/controllers.html">controller</a> and <a href="../general/views.html">views</a>.</p>
<h2>Loading a Helper</h2>
<p>Loading a helper file is quite simple using the following function:</p>
<code>$this->load->helper('<var>name</var>');</code>
<p>Where <var>name</var> is the file name of the helper, without the .php file extension or the "helper" part.</p>
<p>For example, to load the <dfn>URL Helper</dfn> file, which is named <var>url_helper.php</var>, you would do this:</p>
<code>$this->load->helper('<var>url</var>');</code>
<p>A helper can be loaded anywhere within your controller functions (or even within your View files, although that's not a good practice),
as long as you load it before you use it. You can load your helpers in your controller constructor so that they become available
automatically in any function, or you can load a helper in a specific function that needs it.</p>
<p class="important">Note: The Helper loading function above does not return a value, so don't try to assign it to a variable. Just use it as shown.</p>
<h2>Auto-loading Helpers</h2>
<p>If you find that you need a particular helper globally throughout your application, you can tell Code Igniter to auto-load it during system initialization.
This is done by opening the <var>application/config/autoload.php</var> file and adding the helper to the autoload array.</p>
<h2>Using a Helper</h2>
<p>Once you've loaded the Helper File containing the function you intend to use, you'll call it the way you would a standard PHP function.</p>
<p>For example, to create a link using the <dfn>anchor()</dfn> function in one of your view files you would do this:</p>
<code><?=anchor('blog/comments', 'Click Here');?></code>
<p>Where "Click Here" is the name of the link, and "blog/comments" is the URI to the controller/function you wish to link to.</p>
<h2>Now What?</h2>
<p>In the Table of Contents you'll find a list of all the available Helper Files. Browse each one to see what they do.</p>
</div>
<!-- END CONTENT -->
<div id="footer">
<p><a href="#top">Top of Page</a><p>
<p><a href="http://www.codeigniter.com">Code Igniter</a> · Copyright © 2006 · <a href="http://www.pmachine.com">pMachine, Inc.</a></p>
</div>
</body>
</html>
|
