Allow only one number and one decimal point in the HTML text input box

Restrict the user to enter invalid numbers and decimal places, leading to poor price calculation.CodeFor more information, see.

 <  Html  >  
 <  Head  >  
 <  Title  > Text number </  Title  >  
 <  Meta HTTP-equiv  = "Content-Type"  Content  = "Text/html; charset = GBK"  >  
 </  Head  >  
 <  Script  Type  = "Text/JavaScript"  >   
  Function Check (event ){
  VaR  E  =  Window. Event  |  Event;
  VaR  Target  =  E. srcelement |  E.tar get;
  VaR  K  =  E. keycode;
  If  (Isfunkey (k )){
  Return   True  ;
}
 VaR  C  =  Getchar (k );
  If  (Target. value. Length  =   ''   &&  (C  =  '  -  '   |  C  =   '  +  '  )){
  Return   True ;
}
  If  (Isnan (target. Value  +  Getchar (k ))){
  Return   False  ;
}
  Return   True  ;
}
 Function  Isfunkey (CODE ){
  //  8 --> backspace  
//  35 --> end  
//  36 --> Home  
//  37 --> left arrow  
// 39 --> right arrow  
//  46 --> Delete  
//  112 ~ 123 --> F1 ~ F12  
  VaR  Funkeys  =  [  8 ,  35  ,  36  ,  37  ,  39  ,  46  ];
  For (  VaR  I  =   112  ; I  <=   123  ; I  ++  ){
Funkeys. Push (I );
}
  For (  VaR  I  =   0  ; I  <  Funkeys. length; I  ++  ){
  If  (Funkeys [I] =  Code ){
  Return   True  ;
}
}
  Return   False  ;
}
  Function  Getchar (k ){
  If (K  > =   48   &&  K  <=   57  ){
  Return  String. fromcharcode (k );
}
  If (K  > =   96   &&  K  <=   105  ){
  Return  String. fromcharcode (K  -  48  );
}
  If  (K  =   110   |  K  =   190   |  K =   188  ){
  Return   "  .  "  ;
}
  If  (K  =   109  |  K  =   189  ){
  Return   "  -  "  ;
}
  If  (K =   107   |  K  =   187  ){
  Return   "  +  "  ;
}
 Return   "  #  "  ;
}
  </  Script  >  
 <  Style  Type  = "Text/CSS"  >   
Textarea {   
Width  :  200px  ;   
Height  :  80px  ;   
  }   
Span {   
Color  :  # Ff0000  ;   
  }   
  </  Style  >  
 <  Body >  
 <  Input  Style  = "Ime-mode: Disabled ;"  Onpaste  = "Return false"  Onkeydown  = "Return check (event )"  Onkeyup  = "If (isnan (this. Value) | this. value <0 | this. value> 59) This. value = '0 '"  >  
 </  Body  >  
 </  Html  > 

Text number