Function overloading proficient in Javascript

Overloading is a common feature in object-oriented systems. Although JS does not directly support function overloading, function overloading can be implemented in many ways. Every function in JS carries a variable that only works within the range of this function. It is called the parameter argument. It is a dimension array containing all parameters passed to the function, it is not an array in the true sense. It cannot be modified, but can access its elements and attributes.

The following example provides an intuitive understanding:

<SCRIPT type = "text/JavaScript" Language = "JavaScript"> // function of sending a message: sendmessage (MSG, OBJ) {// If the input parameter is two, use OBJ to send the message if (arguments. length = 2) obj. handlemsg (MSG); // if no parameter is input, the error message else if (arguments. length = 0) Alert ("an error occured! "); // If the input parameter is MSG, the message else if (typeof (MSG) =" string ") Alert (MSG) is displayed; // If the input parameter is OBJ, use OBJ to send the message else if (typeof (MSG) = "object") MSG. handlemsg ();} sendmessage ("Hello, world! "); Sendmessage (" how are you? ", {Handlemsg: function (MSG) {alert (" this is a custom message: "+ MSG) ;}}); sendmessage ({handlemsg: function () {alert ("this is a custom message") ;}}); </SCRIPT>