console 命令行工具 X clear

console

function writeDocument(variable) {
    document.write(variable + "<br/>");
}

function countChar(stringValue, char) {
    var charCount = 0;

    for (var i = 0; i < stringValue.length; ++i) {
        if (stringValue.charAt(i).toLowerCase() == char) {
            ++charCount;
        }
    }

    return charCount;
}
var stringValue = "Can you can a can as a Canner can can a can";
writeDocument("There are " + countChar(stringValue, "c") + " 'c' in sentence.");

<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <script>
    </script>
</head>
<body>
    <script>
    </script>
</body>
</html>