10 mini tips for beginners of JavaScript page 1/2

In the previous Programming Language In the ranking, we once introduced the Javascript language, just Article As stated in, JavaScript is not only the most dynamic scripting language, but also 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 Program In the past, JavaScript was often regarded 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: CopyCode The Code is as follows: 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:Copy codeThe Code is as follows: 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 boolean. For example:Copy codeThe Code is as follows: var mystring = '000000 ';
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:Copy codeCode: 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:Copy codeThe Code is as follows: 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:Copy codeThe Code is as follows: function add_nums (){
Return arguments. length;
}
Add_nums (, 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.Copy codeThe Code is as follows: function sum_three_nums (){
If (arguments. length! = 3) throw new error ('received' + arguments. Length + 'parameters and shoshould 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 );