JavaScript expands string functionality through the prototype attribute

String.Length

Function: This is actually an attribute of the String class, but since JavaScript treats both Full-width and Half-width as a single character, there may be a problem in some practical use, and now we are using prototype to make up for this deficiency.

Implementation method:

String.prototype.cnLength = function(){
　　　　var arr=this.match(/[^\x00-\xff]/ig);
　　　　return this.length+(arr==null?0:arr.length);
　　}

Test: Alert ("Easewe space Spaces". Cnlength ())-> display 16

Here are some methods of regular expressions and the coding principle of full-width characters.

Date.daydiff ()

Action: Calculates the time interval (year, month, Day, week) of two date-type variables

Implementation method:

Date.prototype.DayDiff = function(cDate,mode){
　　　　try{
　　　　　　cDate.getYear();
　　　　}catch(e){
　　　　　　return(0);
　　　　}
　　　　var base =60*60*24*1000;
　　　　var result = Math.abs(this - cDate);
　　　　switch(mode){
　　　　　　case "y":
　　　　　　　　result/=base*365;
　　　　　　　　break;
　　　　　　case "m":
　　　　　　　　result/=base*365/12;
　　　　　　　　break;
　　　　　　case "w":
　　　　　　　　result/=base*7;
　　　　　　　　break;
　　　　　　default:
　　　　　　　　result/=base;
　　　　　　　　break;
　　　　}
　　　　return(Math.floor(result));
　　}

Test: Alert (new Date ()). Daydiff (New Date (2002,0,1)))-> display 329

Alert (new Date ()). Daydiff (New Date (2002,0,1)), "M")-> display 10

Of course, it can be further expanded to get the response hours, minutes, or even seconds.