js basic syntax and maven project configuration tutorial case

1. js statement
Second, js array
3. js function
4. Maven
V. Conclusion

1. js statement

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		<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>
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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>
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3. js function

insert image description here

<!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>
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