PHP · Theory

XSS Prevention

Theory

340/352

XSS Prevention

Meera only reaches for XSS Prevention when a XSS Prevention dry-run has to stay correct in a viva board.

Do XSS Prevention once by hand. one XSS Prevention step Meera can write from memory. Change one input. Say the new result out loud.

Without XSS Prevention, a viva board gets messy and a XSS Prevention dry-run is hard to trust.

XSS Prevention shows up in a viva board. Name a XSS Prevention dry-run, not “a real-world scenario”.

XSS Prevention trap — copy-pasting XSS Prevention without a dry-run. Meera loses marks for that every viva.

After XSS Prevention, Meera should still remember copy-pasting XSS Prevention without a dry-run.

One breath for XSS Prevention, then a XSS Prevention dry-run, then copy-pasting XSS Prevention without a dry-run. Sit down.

Exam tip

Say XSS Prevention in one breath, then one XSS Prevention step Meera can write from memory, then copy-pasting XSS Prevention without a dry-run.

Example

<?php
// XSS Prevention
$scores = [80, 90, 70];
$avg = array_sum($scores) / count($scores);
echo "avg=" . number_format($avg, 1) . "\n";
foreach ($scores as $s) {
  if ($s >= 80) echo "high: $s\n";
}

XSS Prevention: scores array, print avg, then high marks. Say the output.

Short notes

DefXSS Prevention — Meera uses it for a XSS Prevention dry-run in a viva board.
RuleXSS Prevention → one XSS Prevention step Meera can write from memory.
RememberXSS Prevention + Apache/Nginx (a viva board).
UseXSS Prevention in a viva board (a XSS Prevention dry-run).
TrapXSS Prevention — copy-pasting XSS Prevention without a dry-run.
ExXSS Prevention → a XSS Prevention dry-run.

PHP · Theory

XSS Prevention

← All stacks

Theory

340/352

XSS Prevention

Meera only reaches for XSS Prevention when a XSS Prevention dry-run has to stay correct in a viva board.

Do XSS Prevention once by hand. one XSS Prevention step Meera can write from memory. Change one input. Say the new result out loud.

Without XSS Prevention, a viva board gets messy and a XSS Prevention dry-run is hard to trust.

XSS Prevention shows up in a viva board. Name a XSS Prevention dry-run, not “a real-world scenario”.

XSS Prevention trap — copy-pasting XSS Prevention without a dry-run. Meera loses marks for that every viva.

After XSS Prevention, Meera should still remember copy-pasting XSS Prevention without a dry-run.

One breath for XSS Prevention, then a XSS Prevention dry-run, then copy-pasting XSS Prevention without a dry-run. Sit down.

Exam tip

Say XSS Prevention in one breath, then one XSS Prevention step Meera can write from memory, then copy-pasting XSS Prevention without a dry-run.

Example

<?php
// XSS Prevention
$scores = [80, 90, 70];
$avg = array_sum($scores) / count($scores);
echo "avg=" . number_format($avg, 1) . "\n";
foreach ($scores as $s) {
  if ($s >= 80) echo "high: $s\n";
}

XSS Prevention: scores array, print avg, then high marks. Say the output.

Short notes

DefXSS Prevention — Meera uses it for a XSS Prevention dry-run in a viva board.
RuleXSS Prevention → one XSS Prevention step Meera can write from memory.
RememberXSS Prevention + Apache/Nginx (a viva board).
UseXSS Prevention in a viva board (a XSS Prevention dry-run).
TrapXSS Prevention — copy-pasting XSS Prevention without a dry-run.
ExXSS Prevention → a XSS Prevention dry-run.

XSS Prevention

Example

Short notes

Questions

XSS Prevention

Example

Short notes

Questions