[php学习十一]javaScript的基本练习2

来源：互联网发布：融云支持java语言编辑：程序博客网时间：2024/05/30 23:31
<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <title>HTML随便练习4</title>    <style>        p{background: center; background-color: #FFA500; text-align: center;}    </style></head><script>    function btnClick(){        try {            /*注意点1:throw抛异常的时候一定要NEW个异常对象,否则获取不到异常信息~~*/            var buf = document.getElementById("IntValue").value.trim();            var y =document.getElementById("InputResult");            if (buf == "") throw new Error("值不能为空");            if (isNaN(buf)) throw new Error("不是数字");            if (buf < 0) throw new Error("不能小于0");            if (buf > 10 ) throw Error("不能大于10");            y.innerHTML="数字正确.";        }        catch (err){            y.innerHTML="错误：" + err.message + "。";        }    }</script><body><input title="输入" type="text" id="IntValue" value="请输入[0..10]的数" style="color:olivedrab ; width: 200px"       onclick="this.value ='' "><div id="InputResult" style="color: brown" ></div><input type="button" onclick="btnClick()" value="确定"><p><small>数组与对象使用</small></p><div id="ArrAndObj"></div><p><small>查找最大的数</small></p><div id="findMax"></div><p><small>闭包调用三次</small></p><div id = "TimeCount"></div><script language="javascript">    function showObj(aobj){        var r = "";        for (var buf in aobj){            /*注意点2:推荐用typeof aobj[buf] == "function"进行类型判断~~*/            if (aobj[buf].constructor.toString().indexOf("Function") > -1){                r += buf + ":" + aobj[buf]() + ";";            }            else{                r += buf + ":" + aobj[buf] + ";";            }        }        return r;    }    var arr = [];    arr[0] = "Hello";    arr[1] = "World";    var  obj = [2];    /*注意点3:一旦以哈希的方式赋值后,就不能用数组的方法了,如length,arr[0]等~*/    obj["a"] = "Hello";    obj["b"] = "World";    obj["c"] = function () {return false};    document.getElementById("ArrAndObj").innerHTML = "arr为数组:" + arr.toString() + ";长度:" + arr.length + "arr[0]=" + arr[0] + "<br>"            +"Obj为对象:" + showObj(obj) + "长度" + obj.length + ";obj['a']或obj.a=" + obj.a;    function findMaxNumber() {        var max = 0;        for (var i = 0; i < arguments.length; i ++){            if (arguments[i] > max){                max = arguments[i];            }        }        return max;    }    document.getElementById("findMax").innerHTML = "(2,3,4,5)最大数为:" + findMaxNumber(2,3,4,5);    /*注意点4:闭包是可访问上一层函数作用域里变量的函数，即便上一层函数已经关闭。*/    var Times = (function () {        var time = 0;        return function () {           return time+=1;        }    })();    document.getElementById("TimeCount").innerHTML = "第一次值:" + Times() + ";第二次值:" + Times() + ";第三次值:" + Times();</script></body></html>
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