check value for null and undefined javascript code example
Example 1: javascript check if undefined or null
if( typeof myVar === 'undefined' || myVar === null ){
// myVar is undefined or null
}
Example 2: javascript check for null variables
var myVar=null;
if(myVar === null){
//I am null;
}
if (typeof myVar === 'undefined'){
//myVar is undefined
}