计算另一个变量中变量值的出现

Question

如何计算一个变量的值在另一个变量中出现的频率，并将该数字存储在第三个变量中。

var theKeyword = "apple";
var theText = "This is an apple and this is an apple, but this is a banana."
var theNumber = (theText.match(/theKeyword/g) || []).length;
console.log(theNumber);

不幸的是，这行不通。