OOQ

#JavaScript #JavaScript / conditional statement / switch The most basic conditional statement is the if. However, the disadvantage is that if there are many values ​​to compare in the conditional expression, the code becomes longer and less readable. In such cases, it is recommended to use switch. grammar switch ( condition ) { case value1: statement1; break; case value2: statement2; break; ... ..

#javascript #javascript conditionals if, else if, else We use if, else if, else when we want to do something when a certain condition is met. grammar if ( condition1 ) { statement1 } Executes statement1 if condition1 is met. if ( condition1 ) { statement1 } else { statement2 } Executes statement1 if condition1 is met, otherwise executes statement2. if ( condition1 ) { statement1 } else if ( cond..

#javascript #javascript typeof operator typeof Operator typeof is an operator that returns the data type of a variable. grammar typeof variable variable contains data or variables. Parentheses are allowed. typeof(variable) The returned values ​​are: undefined: if the variable is not defined or has no value number : if the data type is number string : if the data type is a string boolean : if the..

#javascript The Cpmparison Operator is used to compare the value of a variable with any value or other variable. There are eight comparison operators, but let's take a look at the meaning of each operator. == == is "same". True if the values ​​are equal regardless of variable type. in short 5 == 5 The above content is also correct '5' == 5 The above content is also correct != ! = Is "not the sam..

#Javascript String To use a string as the value of a variable, enclose it in single quotes (') or double quotes ("). var jb = 'Lorem ipsum dolor'; var jb = "Lorem ipsum dolor"; If the string has single quotes, enclose it in double quotes, and if there are double quotes, enclose it in single quotes. var jb = 'Lorem "ipsum" dolor.'; var jb = "Lorem 'ipsum' dolor."; If you have single and double qu..

#Javascript One-line comment Create a one-line comment with //. // single line comment // Before, it's processed by code, // After that, it's processed by comments. for example var jb = 'hi'; // Comment var jb ='hi'; is recognized as code. Multi-line comment If you want to comment out multiple lines, enclose them in / * and * /. /* Comment 1 Comment 2 ​*/ It may be easier to read and may look li..

Javascript JavaScript considers the syntax to end when it breaks. var jb1 = 'Lorem' var jb2 = 'Ipsum' However, if the syntax is not complete, it interprets up to the next line. in short var jb1 = 'Lorem' var jb1 = 'Lorem' The above two methods are the same. Use a semicolon (;) to clearly indicate that the syntax is finished. var jb1 = 'Lorem'; var jb2 = 'Ipsum'; Using a semicolon is optional, bu..

Javascript Insert directly into HTML document This is a method to create a This method is useful if you use JavaScript for some pages or if your JavaScript code is short. Create and load a script file How to link to an HTML document after creating a file containing JavaScript code. Create a file with the following content and save it as hello.js. (The extension of the script file is js.) alert (..