3v4l.org

run code in 300+ PHP versions simultaneously
<?php $width = $height = 1024; $stepSize = 100; for ($x=0; $x < $width; $x+=$stepSize) { for ($y=0; $y < $height; $y+=$stepSize) { echo "Checking pixel at ($x, $y)"; } }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Checking pixel at (0, 0)Checking pixel at (0, 100)Checking pixel at (0, 200)Checking pixel at (0, 300)Checking pixel at (0, 400)Checking pixel at (0, 500)Checking pixel at (0, 600)Checking pixel at (0, 700)Checking pixel at (0, 800)Checking pixel at (0, 900)Checking pixel at (0, 1000)Checking pixel at (100, 0)Checking pixel at (100, 100)Checking pixel at (100, 200)Checking pixel at (100, 300)Checking pixel at (100, 400)Checking pixel at (100, 500)Checking pixel at (100, 600)Checking pixel at (100, 700)Checking pixel at (100, 800)Checking pixel at (100, 900)Checking pixel at (100, 1000)Checking pixel at (200, 0)Checking pixel at (200, 100)Checking pixel at (200, 200)Checking pixel at (200, 300)Checking pixel at (200, 400)Checking pixel at (200, 500)Checking pixel at (200, 600)Checking pixel at (200, 700)Checking pixel at (200, 800)Checking pixel at (200, 900)Checking pixel at (200, 1000)Checking pixel at (300, 0)Checking pixel at (300, 100)Checking pixel at (300, 200)Checking pixel at (300, 300)Checking pixel at (300, 400)Checking pixel at (300, 500)Checking pixel at (300, 600)Checking pixel at (300, 700)Checking pixel at (300, 800)Checking pixel at (300, 900)Checking pixel at (300, 1000)Checking pixel at (400, 0)Checking pixel at (400, 100)Checking pixel at (400, 200)Checking pixel at (400, 300)Checking pixel at (400, 400)Checking pixel at (400, 500)Checking pixel at (400, 600)Checking pixel at (400, 700)Checking pixel at (400, 800)Checking pixel at (400, 900)Checking pixel at (400, 1000)Checking pixel at (500, 0)Checking pixel at (500, 100)Checking pixel at (500, 200)Checking pixel at (500, 300)Checking pixel at (500, 400)Checking pixel at (500, 500)Checking pixel at (500, 600)Checking pixel at (500, 700)Checking pixel at (500, 800)Checking pixel at (500, 900)Checking pixel at (500, 1000)Checking pixel at (600, 0)Checking pixel at (600, 100)Checking pixel at (600, 200)Checking pixel at (600, 300)Checking pixel at (600, 400)Checking pixel at (600, 500)Checking pixel at (600, 600)Checking pixel at (600, 700)Checking pixel at (600, 800)Checking pixel at (600, 900)Checking pixel at (600, 1000)Checking pixel at (700, 0)Checking pixel at (700, 100)Checking pixel at (700, 200)Checking pixel at (700, 300)Checking pixel at (700, 400)Checking pixel at (700, 500)Checking pixel at (700, 600)Checking pixel at (700, 700)Checking pixel at (700, 800)Checking pixel at (700, 900)Checking pixel at (700, 1000)Checking pixel at (800, 0)Checking pixel at (800, 100)Checking pixel at (800, 200)Checking pixel at (800, 300)Checking pixel at (800, 400)Checking pixel at (800, 500)Checking pixel at (800, 600)Checking pixel at (800, 700)Checking pixel at (800, 800)Checking pixel at (800, 900)Checking pixel at (800, 1000)Checking pixel at (900, 0)Checking pixel at (900, 100)Checking pixel at (900, 200)Checking pixel at (900, 300)Checking pixel at (900, 400)Checking pixel at (900, 500)Checking pixel at (900, 600)Checking pixel at (900, 700)Checking pixel at (900, 800)Checking pixel at (900, 900)Checking pixel at (900, 1000)Checking pixel at (1000, 0)Checking pixel at (1000, 100)Checking pixel at (1000, 200)Checking pixel at (1000, 300)Checking pixel at (1000, 400)Checking pixel at (1000, 500)Checking pixel at (1000, 600)Checking pixel at (1000, 700)Checking pixel at (1000, 800)Checking pixel at (1000, 900)Checking pixel at (1000, 1000)

preferences:
235.68 ms | 413 KiB | 315 Q