<!DOCTYPE html>
<html>
<head>
<title>Javascript高级程序设计-第一阶段</title>
</head>
<body>
<script type="text/javascript">
/*
//1、获取逻辑像素
var pageWidth = window.innerWidth;
var pageHeight = window.innerHeight;
console.log("pageWidth:" + pageWidth);
console.log("pageHeight:" + pageHeight);
if (typeof pageWidth != "number") {
if (document.compaMode === "CSS1Compat") {
}
}
//2、获取窗口位置
var leftPos = (typeof window.screenLeft == "number") ? window.screenLeft : window.screenX;
var topPos = (typeof window.screenTop == "number") ? window.screenTop : window.screenY;
console.log("position left:" + leftPos);
console.log("position top:" + topPos);
//2、 两个比较运算符的却别
console.log("===:" + (null === undefined)); //true
console.log("==:" + (null == undefined)); // false
3、 setTimeout() 应用
var date1 = new Date();
console.log(parseInt(date1.getTime()));
var date2 = new Date();
setTimeout("", 2000);
console.log(parseInt(date2.getTime()));
console.log(date1.getTime() - date2.getTime());
4、 clearTimeout(func, time) 应用
function demo() {
var date = new Date();
console.log(date);
}
var t = setInterval(demo, 500);
setTimeout("clearInterval(t)", 3000);
5、 定时器： 所有dom元素渲染完后才开始计时
setTimeout("alert('deefe')", 3000);
//5、闭包
function createFunction() {
var result;
for (var i = 0; i < 10; i++) {
result[i] = function() {
result[i].index = i;
return i;
}
}
console.log(result[0].index);
return result;
}
function createFunction() {
var result = new Array();
for (var i = 0; i < 10; i++) {
result[i] = function(num) {
return function() {
result[i].index = i;
console.log(i);
return num;
};
}(i);
}
return result;
}
console.log(createFunction());
//6、三目运算符
console.log((x > y ? x : y) > z ? (x > y ? x : y) : z);
//7、求最大值
Math.max() 不能传入数组， 只能传入参数列
console.log(max(12, 23, 1));
function max() {
var arr = [12112, 21, 212, 12, 3213];
return Math.max(arr);
}
//8、回调函数，返回上一步操作，每一次结果保存在内存中，占用内存
function factorial1(num) {
if (num > 0) {
return num * factorial1(num - 1);
} else {
return 1;
}
}
//9、回调函数，讲结果返回，不占用多余的内存
function factorial2(num, total) {
if (num > 0) {
return total = num * factorial2(num - 1);
} else {
return 1;
}
}
var n = 10;
console.log("factorial1(" + n + "):" + factorial1(n));
console.log("factorial2(" + n + "):" + factorial2(n));
//10、函数中断方式
function say() {
console.log("1"); // 1
return 0;
console.log("2"); //函数已经结束没有执行
}
中断循环的方式
1.
break
2.
continue
//11、ECMScript 完整的解析器
alert(eval("1+2"));
//12、闰年判断
var j = 1;
for (var i = 1; i <= 3000; i++) {
if (getYear(i)) {
console.log(j + ":" + i);
j++;
}
}
function getYear(year) {
if (year % 400 == 0 || (year % 4 === 0 && year % 100 != 0)) {
return 1;
} else {
return 0;
}
}
//13、push(),pop(),shift(),unshift()区别
var arr = [1, 2, 3];
arr.push(4);
console.log("push(4):" + arr); //1,2,3,4 从尾部添加
var arr = [1, 2, 3];
arr.pop(4);
console.log(arr); //1,2 从尾部出栈
var arr = [1, 2, 3];
arr.unshift(4)
console.log(arr); //4,1,2,3 从头部添加
var arr = [1, 2, 3];
arr.shift(4);
console.log(arr); // 2,3 从尾部添加
//14、++在前面和在后面的区别
var n = 100;
alert(++n); // 101
var m = 100;
alert(m++); //100
//15、条件操作符
console.log(12 > 4 ? "yes" : "no");
*/
</script>
</body>
</html>
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