将js方法名作为参数传给js方法

1，demo1：参数function无参

<script>
function fun1(){
    fun3('fun4');
}

function fun2(){
    fun3('fun5');
}

function fun3(fun){
     eval(fun+'()');
}

function fun4(){
    alert("fun4")
}

function fun5(){
    alert("fun5")
}
</script>

<button onclick="fun1()">button1</button>
<button onclick="fun2()">button2</button>

 2，demo2：参数function有参

<script>
function fun1(){
    fun3('fun4',"param4");
}

function fun2(){
    fun3('fun5',"param5");
}

function fun3(fun,param){
     eval(fun+'("'+param+'")');
}

function fun4(param){
    alert(param)
}

function fun5(param){
    alert(param)
}
</script>

    <button onclick="fun1()">button1</button>
    <button onclick="fun2()">button2</button>