Please help modify this JS$/$HTML program to fit the requirements:

You MUST use the sample code provided.

Modify the code to include the division operator $(\text{'}/\text{'})$ and change the power operator to $\text{'}**\text{'}.$

Ensure that the precedence rules are implemented correctly, with the power operator having the highest precedence, followed by division and multiplication having the same precedence, and finally addition and subtraction having the lowest precedence.

Implement the necessary changes to handle the new operators and precedence rules in the parser.

Incorporate support for white spaces between number and operator and braces. Eg: $(2*2)+1$

Test the parser by evaluating the given mathematical expression:

$5*3+(3-(2+1)*(2**2))-(6/3-3)$ and confirm that the result is $7.$

Save your modified code in an HTML file with an appropriate filename.

Sample code to be modified: