function roman_to_Int(str1) {  
    if(str1 == null) return -1;  
    var num = char_to_int(str1.charAt(0));  
    var pre, curr;  
      
    for(var i = 1; i < str1.length; i++){  
    curr = char_to_int(str1.charAt(i));  
    pre = char_to_int(str1.charAt(i-1));  
    if(curr <= pre){  
    num += curr;  
    } else {  
    num = num - pre*2 + curr;  
    }  
    }  
      
    return num;  
    }  
      
    function char_to_int(c){  
    switch (c){  
    case 'I': return 1;  
    case 'V': return 5;  
    case 'X': return 10;  
    case 'L': return 50;  
    case 'C': return 100;  
    case 'D': return 500;  
    case 'M': return 1000;  
    default: return -1;  
    }  
    }  
    console.log(roman_to_Int('XXVI'));  
    console.log(roman_to_Int('CI'));