JavaScript - What is the difference between call, bind and apply?

The value of this depends on how the code is executed rather how the code has been written. These functions are used to stabilize the value of this.

call and apply are used like this.

function thisLogger(comment) {
console.log(comment + ', this=' + this);
}
var myThis = {'key' : 'value'};
//Fixing the value of this as myThis
//any value including primitive can be sent
thisLogger.call(myThis, 'Sent my this');
//apply is exactly same except the parameters
//are passed as single array argument
thisLogger.apply(myThis, ['Sent my this']);

bind is used to fix the value of this when a function is defined.

var myThis = 'myThis';
var fixedThis = function fixedThis(){
  console.log(this)
}.bind(myThis);
//The value is this is now fixed to myThis
fixedThis(); //print 'myThis'
//Sending new value of this does not change it
fixedThis.call('changedThis'); //print 'myThis'
fixedThis.apply('changedThis'); //print 'myThis'

bind can only be used when it is assigned to some variable. It can’t be used like this.

//CAN NOT BE USED LIKE THIS
function fixedThis(){
  console.log(this)
}.bind(myThis); //This gives error