10 mini tips for beginners of little JavaScript skills (1)

BKJIA's August 24 E-headlines: In the previous programming language rankings, we once introduced the JavaScript language that is just getting started. As stated in the article, JavaScript is not only the most dynamic scripting language, or one of the most useful programming languages. Because most browsers are compatible with it, you can use it in these browsers. JavaScript is accepted quite quickly because it is so simple and widely used. Many programmers used to think of JavaScript as a "Toy language". However, AJAX entered the market and showed the opposite side. It showed completely different capabilities and functions for JavaScript.

As a result of this invention, programmers can now create Web applications with the effects of desktop applications, which is very helpful because data can be changed faster. These are some mini tips that help beginners better use JavaScript. JavaScript is widely used and has so many styles, so it can have a lot of skills. In addition, although it has many programming methods, I have only selected 10 skills. I think these skills are a good starting point for beginners to understand JavaScript.

1. Add an element at the end of an array.

This technique allows you to use the Length attribute to add an element at the end of an array, because the Length attribute is 1 more than the subscript of the last element of the array. This method is the same as the "push" method. For example:

 
 

  
  
 
  
  
var myArray = [];  
  
  
myArray[myArray.length] = 'New Element';  
  
  
 
 
 

2. Adjust the length of an array.

The Length attribute is not read-only, so you can set the value of the Length attribute. In addition, you can use it to increase or decrease the length of the array. For example:

 
 

  
  
 
  
  
var myArray = [1,2,3];  
  
  
myArray.length // 3  
  
  
myArray.length = 2; //Delete the last element  
  
  
myArray.length = 20 // add 18 elements to the array; the elements have the undefined value. 



 
 

3. Use "!" Convert any data type to Boolean

This technology allows you to use "!" Converts any data type, such as string, number, or integer, to a Boolean value. For example:

 
 

  
  
var myString = '23255';  
  
  
typeof myString; //String  
  
  
   
  
  
myString = !!myString;  
  
  
typeof myString  //Boolean 
 
 

4. Convert Number to String

This technique allows you to add an empty string at the end of a number to convert the number to a string. For example:

 
 

  
  
var mynumber = 234;  
  
  
typeof mynumber; //Number  
  
  
   
  
  
mynumber += '';  
  
  
typeof mynumber; //String 
 
 

5. Learn how many variables a function requires.

This is a great technique that lets you know exactly how many variables a function requires. For example:

 
 

  
  
function add_nums(num1, num2){  
  
  
    return num1 + num2;  
  
  
}  
  
  
add_nums.length // 2 is the amount of parameters expected by the function add_nums 
 
 

6. Use the "arguments" object to know how many parameters a function receives.

This technique allows you to use the "arguments" object to understand how many parameters a function receives. For example:

 
 

  
  
function add_nums(){  
  
  
    return arguments.length;  
  
  
}  
  
  
   
  
  
add_nums(23,11,32,56,89,89,89,44,6); //this return the number 9 
 
 

This technique is useful when you need to check the validity of the number of parameters, or when you need to create a function that is not sure about the number of parameters.

 
 

  
  
function sum_three_nums( ){  
  
  
 if(arguments.length!=3) throw new Error('received ' + arguments.length + ' parameters and should work with 3');  
  
  
   
  
  
}  
  
  
   
  
  
sum_three_nums(23,43); //Return the error message  
  
  
   
  
  
function sum_num(){  
  
  
    var total = 0;  
  
  
    for(var i=0;i<arguments .length;i++){  
  
  
        total+=arguments[i];  
  
  
    }  
  
  
    return total;  
  
  
}  
  
  
   
  
  
sum_num(2,34,45,56,56);