js basic syntax and maven project configuration tutorial case
1. js statement
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test js statement</title>
<!-- Embed js code in HTML -->
<script>
// 2. Loop structure // Exercise 3: Output the results in the console. Output how many days it will take to spend 100 million if half of it is spent every day. Use f12 to see var f = 0; //Record the number of days var g = 100000000; //Record the money while( g > 1){
g = g/2; //Change money f++; //Statistics day++
}
console.log(f);
//Exercise 1: Output the results in the console. Use f12 to output 1 to 10 for(var i = 1;i < 11;i++){
console.log(i);
}
//Exercise 2: Output the result in the console, output the sum of 1 to 10, see f12 var e = 0; //Record the sum for(var i = 1;i < 11;i++){
// e = e+ i;
e += i;
}
console.log(e);
// 1. Branch structure //Exercise 4: Pop up the day of the week based on the number entered by the user //var d = prompt("Please enter the day of the week:") ;//The default is string type var d = parseInt( prompt("Please enter the day of the week:") ) ;//string->number
switch(d){
case '1' : console.log("Today is Sunday 1"); // Output the result in the console, use f12 to view case 2 : alert("Today is Sunday 2"); break;
case 3 : alert("Today is Sunday 3"); break;
case 4 : alert("Today is Thursday"); break;
case 5 : alert("Today is Friday"); break;
case 6 : alert("Today is Saturday"); break;
case 7 : alert("Today is Sunday 7"); break;
}
//Exercise 3: Determine whether a common year is a leap year (divisible by 4 and not divisible by 100 | divisible by 400)
var c = prompt("Please enter the year:");
if( c%4==0 && c%100!=0 || c%400==0 ){
alert("leap year");
}else{
alert("Normal Year");
}
//Exercise 2: Receive the score entered by the user and determine the grade to which the score belongs var b = prompt("Please enter the score:");
if( b>=80 && b<=100 )
alert("Excellent");
else if( b>=60 && b<80 )
alert("Medium");
else if( b>=0 && b<60 )
alert("failed");
else
alert("Input error");
//Exercise 1: If a>10, play 1, otherwise play 0
var a = prompt("Please enter an integer");
if( a > 10 ){
alert(1);
}else{
alert(0);
}
</script>
</head>
<body>
</body>
</html>
Second, js array
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test js array</title>
<!-- Arrays in js, characteristics of arrays in Java: length cannot be changed, single data type-->
<script>
//1. js defines an array, features: variable length, rich data types var a = new Array(); //Empty array a = new Array(10,1.1,'hello',true,null,10,1.1); //Change the length of a console.log(a); //View the data in the array console.log(a.length); //Get the length of a a[99] = 0;
console.log(a); //View the data in the array console.log(a.length); //Get the length of a, 100
var b = [ ] ; //empty array b = [1,2,3,"jack",1.1];//assignment for(var i = 0 ; i < b.length ;i++){//traversal console.log(b[i]);//print data according to subscript }
//Exercise 1: Find the sum of even numbers in an array var c = [1,2,3,4,5,6,7,8];
//Equivalent to java's foreach,,,,for...in
for(var i in c){
console.log(c[i]);
}
var d = 0 ; // record and for(var i=0 ;i < c.length ;i++){
if(c[i] % 2 == 0){
d+=c[i]; // sum }
}
console.log(d);
</script>
</head>
<body>
</body>
</html>
3. js function
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Test js function</title>
<script>
// 1. Function writing method 1: a block of code with a specific function // Function declaration: function function name (parameter list) {function body}
function a(){
var b=[1,2,2,3,4];//define array for(var i in b){//traverse array console.log(b[i]);//print data }
}
// Call function a();
// 2. Function writing 2: a block of code with a specific function
//Declare function: var function name = function(parameter list){function body}
var b = function(){
console.log(100);
}
//Call: function name (parameter list); -- The called function must exist! !
b();
//3. Define and call a function with parameters function c(a,b){ //Define a function with parameters console.log(a+b);
}
c("hello",1); //Calling a function with parameters var d = function(a,b){
console.log(a+b);
}
d(1.1,2.6);
//4. Define and call a function with parameters and return value function e(a,b){
return a+b; //Return the result to the caller }
var f = e(1,2);
console.log(f);
var g = function(){
return "hello js" ; //Return the result to the caller }
var h = g();
console.log(h);
//Exercise: Count the number of times character a appears in a string function cishu(str,chara){
var count = 0 ;// record the number of times for(var j = 0 ; j < str.length ;j++){//traverse the string var data = str.charAt(j);//get each character //compare with character a if(data == chara){
//If it is a character, then ++
count++;
}
}
return count; //Return to the caller }
//Call the cishu function to count the number of times character a appears in the string abcaaaaa var count = cishu("abcaaaaa",'a');
console.log("The number of times string a appears is: "+count);
</script>
</head>
<body>
</body>
</html>
4. Maven
V. ConclusionThis article ends here. I hope it can be helpful to you. I also hope that you can pay more attention to more content on 123WORDPRESS.COM! You may also be interested in:
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