抽时间对照着案例撸了一遍，学到了蛮多东西，也有很多疑问，其中有个疑问仍是没有撸明白

graph.width = graph.width; //所谓的巧妙用法？

好了废话不多说,贴出源码：　

    
                 
     
          
       
                
Enter Loan Data:
                
                
Loan Balance, Cumulative Equity, and Interest Payments
           
           
                
Amount of the loan ($):
                
                
            
                 
           
           
                
Annual interest (%):
                
           
           
                
Repayment period (years):
                
           
           
                
Zipcode (to find lenders):
                
           
           
                
Approximate Payments:
                
            Calculate        
           
           
                
Monthly payment:
                
$
           
           
                
Total payment:
                
$
           
           
                
Total interest:
                
$
           
           
                
Sponsors:
                
Apply for your loan with one of these fine lenders:            
         
        
           
      
     

贴上最终效果图：

 

扔在起点摸索中，欢迎大佬解答疑惑。