What is the function JavaScript-

. 1  <! DOCTYPE HTML > 
2  < HTML > 
. 3      < head > 
. 4          < Meta charset = "UTF-. 8" > 
. 5          < title > JavaScript-function What is </ title > 
. 6          < Script type = "text / JavaScript" > 
. 7              function name of the function () {
 8                  function Code
 9              } // function Definition syntax 
10          </ Script > 
. 11      </ head >
12     <body>
13     </body>
14 </html>

To avoid repetition code written troubles, we have completed a particular set of statements function called a constructor, and the reusability of code-readability by calling the function;

Keyword function defined functions
"Function" you get is a function name
"Function Code" is replaced with a specific function completion code
After a good function definition, can not be performed automatically, so the need to call it, just write functions directly in the desired position on the ok

 1 <!DOCTYPE html>
 2 <html>
 3     <head>
 4         <meta charset="utf-8">
 5         <title>JavaScript-什么是函数</title>
 6         <script type="text/javascript">
SUMvar13 isADD2 () {
function12 is* /. 11            } // Function Definition Syntax
10                Function Code
9            function name of the function () {
. 8/ *. 7             
                
                            = . 3 + 2 ;
 14                 Alert (SUM);
 15                 // document.write (SUM); 
16             }
 . 17             ADD2 (); // call the function directly write the name of the function 
18 is          </ Script > 
. 19      </ head > 
20 is      < body > 
21          < the INPUT of the type = "the button" name = "" the above mentioned id = "" value = "click" onclick = "ADD2 ()" /> 
22          <-! click the button, call the function, onclick to click event ->
23     </body>
24 </html>

Related Development: Web page has a button (the name "click me"), after clicking the button calls the function contxt (), pop-up dialog box "Haha, call the function!."

. 1  <! DOCTYPE the HTML > 
2  < HTML > 
. 3  < head > 
. 4  < Meta HTTP-equiv = "the Content-the Type" Content = "text / HTML; charset = UTF-. 8"  /> 
. 5  < title > function call </ title > 
. 6     < Script type = "text / JavaScript" > 
. 7         contxt () // defined function 
. 8        {
 . 9           Alert ( " ha, the calling function! " );
10       }
11    </script>
12 </head>
13 <body>
14    <form>
15       <input type="button"  value="点击我" onclick="    " />  
16    </form>
17 </body>
18 </html>

What is the function JavaScript-

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