Email Validation

Email Validation

// 12/23/2015
// Write a function to test whether a given input is a valid email address.

// For the purposes of this kata, here is what makes a valid email:

// At least one letter character at the beginning >>>>>
// All characters between the first character and the @ (if any) 
// must be letters, numbers, or underscores >>>>>
// There must be an @ character (after the points listed just now) >>>>>
// After the @ character, there must be at least one word character (letter, 
// number, or underscore) or hyphen
// The email must end with at least one set of a dot followed by one or more 
// word characters.

// The input must NOT be case-sensitive
// The function should return true or false.

function validate(input){
    input = input.toUpperCase();
    
    var code1stletter=input.charCodeAt(0)
    var charactersbetween=input.split("@");
    
    if(input.indexOf("@")===-1){
        return false;
    }
    
    if(input.indexOf(".")===-1){
        return false;
    }
    
    var lettersBeforeAt=charactersbetween[0];
   
    if(!(code1stletter<=90 && code1stletter>=65)) {
        return false;
    }
    
    for( var i=1;i<lettersBeforeAt.length; i++){
        var ch = lettersBeforeAt.charCodeAt(i);
        if(!((ch<=90 && ch>=65) || (ch<=57 && ch>=48) || (ch===95))){
            return false;
        }
    }
    
    var lettersAfterAt=charactersbetween[1];
    console.log('Letters after at', lettersAfterAt)
    
           
    var lettersBeforeDot=lettersAfterAt.split(".")[0]
    console.log('Letters before dot', lettersBeforeDot)
    console.log('length of letters before dot', lettersBeforeDot.length)
    
    if(lettersBeforeDot.length===0){
        return false;
    }
    
    for (var j=0; j<lettersBeforeDot.length; j++){
        console.log('inside for loop chekcing letters before dot')
        var ch1 = lettersBeforeDot.charCodeAt(j);
        if(!((ch1<=90 && ch1>=65) || (ch1<=57 && ch1>=48) || (ch1===95) || (ch1===45))){
            return false;
        }
    }
    
    var lettersAfterDot=lettersAfterAt.split(".")[1]
        // console.log(lettersAfterDot)
    
     for (var z=0; z<lettersAfterDot.length; z++){
        var ch2 = lettersAfterDot.charCodeAt(z);
        if(!((ch2<=90 && ch2>=65) || (ch2<=57 && ch2>=48) || (ch2===95) || (ch2===45))){
            return false;
        }
    }
    
    
    return true;
}

validate('abc@.com')