如果php变量链接为null，则禁用href标记

Question

Below variable are stored in mysql table but sometimes some links are empty.How to check if each one is NULL and then disable if content is NULL (0) just to not be selected, because if they empty they holds main link of article.

<?php
echo "<span><strong>DOWNLOADs<strong></span><br/><br>
    <a href=".$link1.">link</a><br/>
    <a href=".$link2.">link1</a><br/>
    <a href=".$link3.">link2</a><br/>";
?>

Answer 1

Check if a link is empty before outputing it :

<?php
echo "<span><strong>DOWNLOADs<strong></span><br/><br>";

if (!empty($link1)) {
    echo "<a href=\"".$link1."\">link</a><br/>";
}

... and so on

Answer 2

This will disable it, instead of masking

By using inline ternary operator over empty() function who : Determine whether a variable is empty

$var = (condition) 
? 'value_0'  // if true
: 'value_1'  // if false

Look for the documentation : Ternary comparison operator

<?php

$link2 = "http://someurl..";

echo "<span><strong>DOWNLOADs<strong></span><br/><br>
    <a ".(!empty($link1) ? "href='$link1'":"").">link</a><br/>
    <a ".(!empty($link2) ? "href='$link2'":"").">link1</a><br/>
    <a ".(!empty($link3) ? "href='$link3'":"").">link2</a><br/>";
?>

Will ouput whole tags link preserved to make only != null active

<span><strong>DOWNLOADs<strong></span><br/><br>
    <a>link</a><br/>
    <a href='http://someurl..'>link1</a><br/>
    <a>link2</a><br/>