Data types in JavaScript

Data types in JavaScript

Here are just a few simple notes!

//Boolean Type Drop   varA= ";//empty string converted to False   varb= ' 123 '//non-idling into true    varIsa=Boolean (a); varisb=Boolean (b); Alert (ISA); //falsealert (ISB);//ture    //so    functionshow001 () {varMessage= ' 123 '; if(message) {//A conversion is done by default here.Alert (' Not empty '); }Else{alert (' Empty. '); }    varValue//This declaration, however, is not assigned by default initialized to undefined    varobj=NULL;//if the variable will be used to receive a pointer to an object that is best assigned to a null empty objectAlert (Boolean (value)); if(value) {Alert (' True '); }Else{alert (' false ');//this is the line.    }        if(obj!=NULL){            }Else{        }    //therefore, in the declaration of variables, according to the actual situation to assign value;    //undefined null "//notice three kinds of empty values drop  }    //about Nan and isNaN ()    functionshow002 () {//determine if an X can be replaced with a number        //can be converted to non-Nan        //can't convert is NanAlert (IsNaN (NaN));//true        //Example One:        varTemp=parseint (' Blue ');       Alert (temp); //Result: NaNAlert (IsNaN (temp))//true cannot be converted to numeric value        //Example Two:        varStr= ' Red '; Alert (IsNaN (str))//true                varStrnum= ' 123 '; Alert (IsNaN (Strnum)); //false                //attention, even a special one!        varValue1=number (true);//1        varValue2=number (false);//0                //soAlert (IsNaN (true))//falseAlert (IsNaN (false))//false            }    //conversion between numeric types drop Yes    //number of values between the amount of exchange;    //Number parseint parsefloat ();

Data types in JavaScript