console 命令行工具 X clear

console

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

writeDocument(welcomeString);
writeDocument(welcomeString.length);

writeDocument("//---case-------------");
writeDocument(welcomeString.toLowerCase());
writeDocument(welcomeString.toUpperCase());

writeDocument("//---caseAt-------------");
writeDocument(welcomeString.charAt(2));
writeDocument(welcomeString.charAt(6));

writeDocument("//---substring-------------");
writeDocument(welcomeString.substring(3));
writeDocument(welcomeString.substring(0,2));

writeDocument("//---replace-------------");
var sentence="we have fun in our class.do u have fun in your class?"
writeDocument(sentence);
writeDocument(sentence.replace("class","programing class"));
writeDocument(sentence.replace(/class/g,"programing class"));

writeDocument("//---replace-------------");
writeDocument(welcomeString.split(""));
writeDocument(sentence.split(" "));
writeDocument(sentence.split("."));

writeDocument("//---indexOf/lastIndexOf/match/search-------------");
writeDocument(sentence.indexOf("class"));
writeDocument(sentence.lastIndexOf("class"));
writeDocument(sentence.match(/class/g));
writeDocument(sentence.search(/class/g));

writeDocument("//---case2----------------");
function countChar(stringToCount, c) {
    var charCount = 0;
    for(var i=0;i<stringToCount.length;i++){
        var char=stringToCount.charAt(i);
        if(char.toLowerCase()=="c"){
            charCount++;
        }
    }
    return charCount;
}
var stringToCount = "Can you can a can as a Canner can can a can";
writeDocument("There are " + countChar(stringToCount, "c") + " c in " + stringToCount); 

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

writeDocument("数组创建---------------------")
var arr=["HTML","CSS","JavaScript","jQuery","Vue.js"];

writeDocument(arr);

writeDocument("数组下标取值---------------------")
writeDocument(arr[2]);

writeDocument("数组赋值---------------------")

arr[4]="React.js";

writeDocument(arr);

arr[5]="arr.js";

writeDocument(arr);

arr[8]="Angular.js";

writeDocument(arr);

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

</head>
<body>
    <script type="text/javascript">
    </script>
   
</body>
</html>