（1）点击事件写法如下，这里会先显示文本，点击之后弹出对话框。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning">My name is Burning</p>
<script type="text/javascript">
window.onload = function(){
var bur = document.getElementById("Burning");
bur.onclick = Hello;
function Hello(){
alert("Hello world");
}
}
</script>
</body>
</html>（2）这样些会首先弹出对话框，然后显示文本。这个的原因百度了一下，没懂！
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning">My name is Burning</p>
<script type="text/javascript">
window.onload = function(){
var bur = document.getElementById("Burning");
bur.onclick = Hello();
function Hello(){
alert("Hello world");
}
}
</script>
</body>
</html>（4）这里会先显示文本，点击之后弹出对话框。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning" onclick="Hello()">My name is Burning</p>
<script type="text/javascript">
//var bur = document.getElementById("Burning");
//bur.onclick = Hello();
/*if (typeof Hello == "function"){
console.log("right");
}*/
function Hello(){
alert("Hello world");
}
</script>
</body>
</html>（5）只显示文本，点击事件不好使。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning" onclick="Hello">My name is Burning</p>
<script type="text/javascript">
//var bur = document.getElementById("Burning");
//bur.onclick = Hello();
/*if (typeof Hello == "function"){
console.log("right");
}*/
function Hello(){
alert("Hello world");
}
</script>
</body>
</html>（6）同（1）
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning">My name is Burning</p>
<script type="text/javascript">
window.onload = function(){
var bur = document.getElementById("Burning");
console.log(bur);
bur.onclick = function(){
/*if (typeof Hello == "function"){
console.log("right");
}*/
alert("Hello world");
};
}
</script>
</body>
</html>（7）同（2）
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning">My name is Burning</p>
<script type="text/javascript">
window.onload = function(){
var bur = document.getElementById("Burning");
console.log(bur);
bur.onclick = function(){
/*if (typeof Hello == "function"){
console.log("right");
}*/
alert("Hello world");
}();
}
</script>
</body>
</html>一段小代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>test for function</title>
</head>
<body>
<p id="Burning">My name is Burning</p>
<script type="text/javascript">
window.onload = function(){
var bur = document.getElementById("Burning");
console.log(bur);
//bur.onclick = Hello;
if (typeof Hello() == 'function')
{
console.log("Hello world");
}//typeof Hello()会执行Hello程序
function Hello(){
alert("Hello world");
}
}
</script>
</body>
</html
