Javascript-javascript tutorial

This article describes how to generate random numbers that are not repeated in javascript within a specified range and related examples. If you need them, refer. Source of question: one test question when learning jQuery in MOOC.

Initial:
 
 

  
  
Only 5 elements are displayed.
  
  
Element, including the last
  
  
"More" characters are displayed in the element. When you click "more", the content of the link becomes "simplified". At the same time, 
   

     Show all 
    
Element. When you click the "simplified" link, its content changes to "more". At the same time, 
     

       Only the last element is displayed. 
      
Five elements, including.
 
     
 
   
 
 

Core point: He didn't tell which ones to hide

So I want to list eight

Elements, points simplify random hiding of the first seven

Three of the elements.

Ideas:

① From 0 ~ Generate three random numbers in Step 6.

② Determine whether the three random numbers are equal. If they are not equal, perform the hidden operation.

③ If a random number already exists, re-execute the function.

Implementation: Generate 0 ~ A Random Number of 6

The Code is as follows:

Var ran1 = parseInt (Math. random () * 7); // Math. random () generates a random number [)

Complete code: