5.if语句
<![CDATA[
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>js基础-分支结构-if语句</title>
<style type="text/css">
</style>
<script type="text/javascript">
function gosum(){
var x=59;
var y=70;
if (x>y){
document.getElementById("sum").innerHTML="x比较大";
}else if(x==y){
document.getElementById("sum").innerHTML="x与y相等";
}else{
document.getElementById("sum").innerHTML="x比较小";
}
/*结果输出在页面中
document为文档节点
getElementById为方法，根据id获得节点
innerHTML在节点写入内容。
*/
}
</script>
</head>
<body>
<span>5.if语句</span><hr>
<span id="sum"></span><br>
<button id="go" onclick="gosum()">运行</button>
<hr>
</body>
</html>
]]>