摘要：$.fn 阅读全文

摘要：//$c = $a ?? $b; 等效 $c = isset($a) ? $a : $b; //$c = $a ?: $b; 等效 $c = $a ? $a : $b; $a = 'a'; $b = 'b'; $c = $a ?? $b; //a $c = $a ?: $b; //a $a = false; $b = 'b'; $c = $a ?? $b; //false $c = ... 阅读全文