如何基于先前的回声词回显一个单词

I have a form input and if script receive word tip (see if statement), it echo "do this" This work good

Now I want to echo another word based on previous word "do this" with if statement, but this not work

$at=(stripos($a, 'tip') === 0);
if ($at == true) {echo "do this";}
if (echoword == do this) {echo "do that";}

you cant not rely on "previous echo" just rely on condition like this:

$at=(stripos($a, 'tip') === 0);
if ($at == true) {
echo "do this";
echo "do that";
}

becaus in this case your "previous echo" depends only on that condition

IF - is a basic control structure. http://php.net/manual/en/control-structures.elseif.php

I believe you want to do it like this

$at=(stripos($a, 'tip') === 0);
if ($at == true) {
    $echoword="do this";
    echo $echoword;
}
if (isset($echoword) && $echoword == 'do this'){
     echo "do that";
}

Which one you prefer?
1. Put your code in existence if statement.

$at=(stripos($a, 'tip') === 0);
if ($at == true) {echo "do this"; echo "do that";}

2. Use $at whenever you want to write related thing.

$at=(stripos($a, 'tip') === 0);
if ($at == true) {echo "do this";}
if ($at) {echo "do that";}

3. Store the echoed word in variable

$at=(stripos($a, 'tip') === 0);
$echoed = '';
if ($at == true) {echo "do this"; $echoed = "do this";}
if ($echode == "do this") {echo "do that";}