//Use this function to validate email addresses
//This function thus simply makes sure the email address has one (@), atleast one (.). 
//It also makes sure that there are no spaces, extra '@'s or a (.) just before or after the @. 
//It also makes sure that there is atleast one (.) after the @
function Emailcheck(str) {

    var at = "@"
    var dot = "."
    var lat = str.indexOf(at)
    var lstr = str.length
    var ldot = str.indexOf(dot)
    if (str.indexOf(at) == -1) {
        alert("Please enter a valid E-mail address")
        return false
    }

    if (str.indexOf(at) == -1 || str.indexOf(at) == 0 || str.indexOf(at) == lstr) {
        alert("Please enter a valid E-mail address")
        return false
    }

    if (str.indexOf(dot) == -1 || str.indexOf(dot) == 0 || str.indexOf(dot) == lstr) {
        alert("Please enter a valid E-mail address")
        return false
    }

    if (str.indexOf(at, (lat + 1)) != -1) {
        alert("Please enter a valid E-mail address")
        return false
    }

    if (str.substring(lat - 1, lat) == dot || str.substring(lat + 1, lat + 2) == dot) {
        alert("Please enter a valid E-mail address")
        return false
    }

    if (str.indexOf(dot, (lat + 2)) == -1) {
        alert("Please enter a valid E-mail address")
        return false
    }

    if (str.indexOf(" ") != -1) {
        alert("Please enter a valid E-mail address")
        return false
    }

    return true
}



function ReplaceChar(string, text, by) {
    // Replaces text with by in string
    var strLength = string.length, txtLength = text.length;
    if ((strLength == 0) || (txtLength == 0)) return string;

    var i = string.indexOf(text);
    if ((!i) && (text != string.substring(0, txtLength))) return string;
    if (i == -1) return string;

    var newstr = string.substring(0, i) + by;

    if (i + txtLength < strLength)
        newstr += ReplaceChar(string.substring(i + txtLength, strLength), text, by);

    return newstr;

}