関連ワード:  javascript if variable is undefined or null    javascript check variable is undefined or null    javascript check if var is undefined or null    js check if var is undefined or null    javascript check if variable is not undefined or null    javascript check if variable is undefined null or empty    javascript check if variable is undefined or empty    javascript check if variable is undefined or empty string    javascript check if variable is not null or undefined or empty string    javascript check if variable is not null or undefined or empty  
結果 : javascript if variable is undefined or null