How to Generate Noise with Canvas デモページ(当方作成) [ad#ad-2] JavaScript function generateNoise(opacity) { if ( !!!document.createElement('canvas').getContext ) { return false; } var canvas = document.createElement('canvas'), ctx = canvas.getContext('2d'), x, y, r, g, b, opacity = opacity || .2; canvas.width = 100; canvas.height = 100; for ( x = 0; x < canvas.width; x++ ) { for ( y = 0; y < canvas.heigh