JavaScript语法应用-猜数字案例
案例思路与技巧:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>猜数字</title>
<script type="text/javascript">
//在页面内容加载前生成随机数
var ranNum = parseInt(Math.random()*100);
alert(ranNum);
function guess(){
//获取文本框中的值
var num = document.getElementById("num").value;
//判断该值是否为数字
var span = document.getElementById("result");
if(isNaN(num)){
span.innerHTML="请输入数字";
}else{
//是数字,与随机数比较
if(num>ranNum){
span.innerHTML="大了";
}else if(num<ranNum){
span.innerHTML="小了"
}else{
span.innerHTML="对了";
}
}
}
</script>
</head>
<body>
<input type="text" id="num">
<input type ="button" value="猜"
onclick="guess();">
<span id="result"></span>
</body>
</html>
最终页面显示效果:
A:
B:
C: