JAVASCRIPT

js setinterval run immediately

function foo() {
   // do stuff
   // ...

   // and schedule a repeat
   setTimeout(foo, delay);
}

// start the cycle
foo();

interval manage for javascript

var IntervalManager =
{
 /*  

 set : Set an interval using setInterval and store its ID
  IntervalManager.set( "uniqueID", function reference, milliseconds );    

 clear : Clear an interval and forget its ID
  IntervalManager.clear( "uniqueID" );

 any : Detect if any intervals are active. Returns ID of first active or false.
  if( IntervalManager.any() )
   {...}

 clearAll : Clears all intervals whose IDs are stored and forgets their IDs 
  IntervalManager.clearAll();  

 */

 intervals : [/*28432953637269707465726C61746976652E636F6D*/],

 set : function( intervalID, funcRef, period )
 {
  if( !this.intervals[ intervalID ] )  

   this.intervals[ intervalID ] = setInterval( funcRef, period );
  else
   alert("Attempted to set " + intervalID + ' more than once.');
 },  

 clear : function( id )
 {
  clearInterval( this.intervals[ id ] );  

  delete this.intervals[ id ];  

 },

 clearAll : function()
 {
  var table = this.intervals;  

  for( var i in table )
  {
   clearInterval( table[ i ] );
   delete table[ i ];  

  }      

 },

 any : function()
 {
  var table = this.intervals, found = false;  

  for( var i in table )
   if( table[ i ] !== null )
   {
    found = table[ i ];  

    break;  

   }

  return found;
 }   

}

interval in javascript

// variable to store our intervalID
let nIntervId;

function changeColor() {
  // check if already an interval has been set up
  if (!nIntervId) {
    nIntervId = setInterval(flashText, 5);
  }
}

function flashText() {
  const oElem = document.getElementById("my_box");
  if (oElem.className === "go") {
    oElem.className = "stop";
  } else {
    oElem.className = "go";
  }
}

function stopTextColor() {
  clearInterval(nIntervId);
  // release our intervalID from the variable
  nIntervId = null;
}

document.getElementById("start").addEventListener("click", changeColor);
document.getElementById("stop").addEventListener("click", stopTextColor);

javascript setinterval run immediately

foo()
setInterval(foo, delay)

// OR

function foo() {
   // ...
   setTimeout(foo, delay)
}
foo()

how to do a function after a set interval js

function sayHi() {
  alert('Hello');
}
//Do a function at a set interval continuously
setTimeout(sayHi, 1000);
//Do a function once after a set interval
setTimeout(sayHi, 1000);