2020-02-16 标签:asp,实现,智能,搜索,代码,function,autokey,strkey,const,lngsubkey,lnglenkey,len,select,case,若为,转到

2020-02-16 标签:js,left,right,mid,函数,javascript,等价,function,mainstr,lnglen,return,substring,else,n,ull,alert,length,starnum,endnum

在JAVASCRIPT中LEFT，RIGHT，MID函数的等价函数function left(mainStr,lngLen) {if (lngLen>0) {return mainStr.substring(0,lngLen)}else{return null}}function right(