判別變數a是否有被設置
"; $a = "test"; var_dump(isset($a)); // TRUE echo "判別變數b是否有被設置
"; $b; var_dump(isset($b)); // FALSE echo "判別變數c是否有被設置
"; $c = NULL; var_dump(isset($c)); // FALSE //字體顏色：https://www.w3schools.com/css/css_colors.asp //字體粗細：https://www.w3schools.com/cssref/pr_font_weight.asp //字體字型：https://www.w3schools.com/css/css_font.asp ?>