function floor(number)
            {
            	return Math.floor(number*Math.pow(10,2))/Math.pow(10,2);
            }
            
            function calculatemortgage()
            {
            
            var int_f = document.getElementById("mcalc_interest_rate");
            var yrs_f = document.getElementById("mcalc_years");
            var amt_f = document.getElementById("mcalc_loan_amount");
            
 
            var interest_rate = int_f.options[int_f.selectedIndex].value;
            var years = yrs_f.options[yrs_f.selectedIndex].value
            var loan_amount = amt_f.value; 
            
            var mpd = document.getElementById("monthly_payment_div");
            
            
            if(!(loan_amount > 0)){
               mpd.innerHTML = "<table><tr><td height='10' align='left'></td></tr><tr><td align='center' class='calculator_hide_text'>Enter a number for the loan amount.</td></tr></table>"; 
            }
            
            else if(int_f.selectedIndex == 0){
                mpd.innerHTML = "<table><tr><td height='10' align='left'></td></tr><tr><td align='center' class='calculator_hide_text'>Select an interest rate.</td></tr></table>";
            }
            
            else if(yrs_f.selectedIndex == 0){
                mpd.innerHTML = "<table><tr><td height='10' align='left'></td></tr><tr><td align='center' class='calculator_hide_text'>Select the term in years.</td></tr></table>";
            }
            
            else{
                var monthly_interest = interest_rate / 1200;
                var base = 1;
                var mbase = 1 + monthly_interest;
                for (var i=0; i < (years * 12); i++)
                {
                	base = base * mbase
                }
                var monthly_payment = floor(loan_amount * monthly_interest / ( 1 - (1/base)))
    			
    			
    			mpd.innerHTML = "<table><tr><td height='10' align='left' class='calculator_text'>Monthly Installment</td></tr><tr><td align='left' class='calculator_hide_text' style='padding-left:10px;'>$ " + monthly_payment+"</td></tr></table>";
			}
			
            }