What is the journal entry for salary paid in advance?.

You can journalize the following:

DR. prepaid salaries (Employee name)
CR. Bank
And when the salary is due you should record the following:
Dr. Salaries Expense
Cr. Prepaid salaries (Employee name)
You can also use the employee account instead of prepaid expense.

Salary advance paid to Mr.A

1.when paid:

Adv payroll 1000
Bank 1000

2.When recovered...

Payroll 1500
Adv payroll 1000
Bank 500