How many times does a character occur?

// Write a function that takes two strings (a and b) as arguments
// Return the number of times a occurs in b
function
myFunction
(
a, b
)
{

return
}
Test Cases:
myFunction('m', 'how many times does the character occur in this sentence?')
Expected
2
myFunction('h', 'how many times does the character occur in this sentence?')
Expected
4
myFunction('?', 'how many times does the character occur in this sentence?')
Expected
1
myFunction('z', 'how many times does the character occur in this sentence?')
Expected
0