<html lang="en">  
<head>  
    <meta charset="UTF-8">  
    <title>javascript不同类型数据之间运算的转换</title>
</head>  
<body>
<script type="text/javascript">
    var result = null + 1;
    console.log(result);  //1
    result = undefined + 1;
    console.log(result);  //NaN
    result = false + 1;
    console.log(result);  //1    
    result = true + 1;
    console.log(result);  //2   
    result = '6' + 1;
    console.log(result);  //61       
    result = '6' - 1;
    console.log(result);  //5
    result = 'a' + 1;
    console.log(result);  //a1       
    result = 'a' - 1;
    console.log(result);  //NaN   
    result = null + undefined;
    console.log(result);  //NaN
    result = null + 'a';
    console.log(result);  //nulla
    result = null - 'a';
    console.log(result);  //NaN
    result = undefined + 'a';
    console.log(result);  //undefineda    
    result = undefined - 'a';
    console.log(result);  //NaN  
    result = true + 'a';
    console.log(result);  //truea  
    result = true - 'a';
    console.log(result);  //NaN 
    result = false + 'a';
    console.log(result);  //falsea      
    result = 66 + 'a';
    console.log(result);  //66a      
    result = null + false;
    console.log(result);  //0      
    result = null + true;
    console.log(result);  //1     
    result = true + false;
    console.log(result);  //1       
    result = false - true;
    console.log(result);  //-1
    result = true + undefined;
    console.log(result);  //NaN   
    result = false + undefined;
    console.log(result);  //NaN  
    result = 1 + NaN;
    console.log(result);  //NaN 
    result = 'a' + NaN;
    console.log(result);  //aNaN     
    result = 1 + 2 + '3';
    console.log(result);  //33      
    result = 1 + (2 + '3');
    console.log(result);  //123      
    result = 1 + true + undefined + 's'; // 1+1+NaN+'s'=2+NaN+'s'=NaN+'s'=NaN
    console.log(result);  //NaNs
</script>
</body>  
</html>
                










