The American Heart Association recommends that when you exercise, you stay within 50 to 85 percent of your maximum heart rate. Th is range is called your target heart rate. One common formula for calculating maximum heart rate is to subtract your age from 220. Create a Web page that you can use to calculate your target heart rate. Use a form that contains a text box in which users can enter their age, and a command button that uses an onclick event handler to call a function named calcHeartRate(). Within the calcHeartRate(),include a statement that calculates the maximum heart rate and assigns the result to a variable. Use two other statements that calculate the minimum (50%) and maximum (85%) target heart rates. To calculate the minimum target heart rate, you use the formula maximum_heart_rate * .5, and to calculate the maximum target heart rate, you use the formula maximum_heart_rate * .85. After you calculate the minimum and maximum target heart rates, display the result in another text box in the form. For example, for someone 35 years old, the target heart rate text box should display “92 to 157 beats per minute”. Save the document as TargetHeartRate.html.