在html源代码中回显全局变量

Question

I have two global variables declared in my config.php file, I would like to call one of these depending on results from another page however I need some help with my syntax.

It simply add a class to the button (btn-success or btn-default)

config.php

define("BTN_SUCCESS", "btn-success");
define("BTN_DEFAULT", "btn-default");

I want to do something like the following but it doesn't work it simply prints out the names in my html source;

echo '<td>
<button id="fav" type="button" class="btn '.BTN_SUCCESS. || 'BTN_DEFAULT''"></button>
</td>';

If I insert either of them individually they work but it's not what I want, for example;

echo '<td>
<button id="fav" type="button" class="btn '.BTN_SUCCESS.'"></button>
</td>';

I want an or operator in there - is this possible? It's probably something simple. Quite new to php so any help is appreciated.

Answer 1

Try this

echo '<td>
<button id="fav" type="button" class="btn '.(BTN_SUCCESS?:BTN_DEFAULT).'"></button>
</td>';

The parenthesis is shorthand for

if(BTN_SUCCESS) 
    echo BTN_SUCCESS;
 else
    echo BTN_DEFAULT;

The if-condition above can be shortened using ternary operators:

echo BTN_SUCCESS ? BTN_SUCCESS : BTN_DEFAULT;

And if you want to echo the value of the condition (in this case BTN_SUCCESS) if it's truthful you can shorten it even more by removing the middle part (as of PHP 5.3):

echo BTN_SUCCESS ?: BTN_DEFAULT;