Coding a Web Page Calculator

The other function, operator(), carries out operations. It has to carry out the ADD, SUBTRACT, MULTIPLY and DIVIDE operations. It also has to store, clear the display and do evaluation (Enter). This is its function skeleton with its associated global variables:

var evalString = ""

var memVar = "";

var toClearDisplay = false;

function operator(ID)

{

//first construct the first part of the eval argument using JavaScrip’s top level eval() function

switch (ID)

{

case "BP":

//join “ “ and “+” and “ “ to the evaluation string, evalString.

break;

case "BMI":

//join “ “ and “-” and “ “ to the evaluation string, evalString.

break;

case "BX":

//join “ “ and “*” and “ “ to the evaluation string, evalString.

break;

case "BD":

//join “ “ and “/” and “ “ to the evaluation string, evalString.

break;

case "BMP":

// Store display content into memory

break;

case "BMM":

//Clear the display and do other associated things.

break;

case "BEQ":

//Evaluate the mathematical expression.

break;

}

}