Summary of three ways to define functions in JavaScript_javascript skills

var func = function()
{
/*body code*/
}

function func()
{
//body code
}

var func = new Function("/*parameters */","/*body code*/");

//Declare a variable and define the variable Expression reference
var test = function()
{
alert("reference test");
}
//Define an expression and save its address information in test1
function test1()
{
alert("reference test1");
}
//Pass the expression referenced by test to reference
var reference = test;
//Pass the address of the test1 expression to reference1
var reference1 = test1;
//Change the reference of the variable test
test = function()
{
alert("new test ");
}
//Redefine the data in the test1 address
function test1()
{
alert("new test1");
}
alert( reference);//The expression it refers to does not change
alert(reference1);//Since reference1 is a reference to the test1 address, when the content represented by the test1 address changes, the content of reference1 also changes