check if undefined or null javascript code example

Example 1: javascript check if undefined or null

if( typeof myVar === 'undefined' || myVar === null ){
    // myVar is undefined or null
}

Example 2: check if variable is undefined or null jquery

if (variable == null) {
    // variable is either null or undefined
}

Example 3: javascript check if null

if (variable === null) { //Executes only if variable is null but not undefined
  //Code here
}

if (variable == null) { //Executes if variable is null OR undefined
  //Code here
}

Example 4: javascript check for null variables

var myVar=null;

if(myVar === null){
    //I am null;
}

if (typeof myVar === 'undefined'){
    //myVar is undefined
}

Example 5: javascript syntax for check null or undefined or empty

if (typeof value !== 'undefined' && value) {
    //deal with value'
};