<script language="javascript">
/*
//变量的优先级别
var scope = "globle variable";
function checkscope() {
var scope = "local variable";
document.write(scope);
}
checkscope();//调用函数,输出结果
*/
//javascript没有块级作用域
/*
function test(q) {
var i = 0;
if(q == 2) {
var j = 0;
for(var k = 0;k < 10;k ++) {
document.write(k + " ==== ");
}
document.write("<br>" + k); //这一段为什么没有执行 ^_^!!!
}
document.write("<br>" + j);
}
test(2);
*/
/*
var today = new Date(); //new创建对象
alert(today);
today = null;
alert(today);
var myArray = ['a','b','c','d'];//创建数组
document.write(myArray + "<br>");
delete myArray[3];
document.write(myArray + "<br>"); //用delete删除对象的属性或移除数组的元素
//运算符 () 调用方法
*/
/*
//while控制语句
document.write("<table border='1'>");
var i = 0;
while(i < 10) {
document.write("<tr>");
document.write("<td>");
document.write(i);
document.write("</td>");
document.write("</tr>");
i ++;
}
document.write("</table>");
*/
/*
//用for打印乘法表
document.write("<table border='1'>");
for(var i = 1;i <= 9;i ++) {
document.write("<tr>");
for(var j = 1; j <= i;j ++) {
document.write("<td>");
document.write(i + " * " + j + " = " + (j * i));
document.write("</td>");
}
document.write("</tr>");
}
document.write("</table>");
*/
/*
//有返回值的函数调用
function getMax(x,y) {//此处不能用var x , var y
if(x > y) {
return x;
} else {
return y;
}
}
var m = getMax(1,2);
alert(m);
*/
/*
//全局变量 :变量不在函数中
//局部变量 :变量定义在函数中
//参数变量可变的函数,arguments
function testparams() {
var params = "";
for(var i = 0;i < arguments.length;i ++) {
params += arguments[i];
}
alert(params);
}
testparams("liusheng",23);
*/
/*
//数值处理函数
//parseInt(numString,[radix]) radix是几进制 123abc能转 abc123不能转
//假如不能转返回 NaN 要用 isNaN判断 或者是用temp == NaN
//document.write(parseInt("ad234",10));
function testParse(x) {
var temp = parseInt(x);
if(temp == NaN) {
alert("NaN");
} else {
alert(temp);
}
}
testParse("123abc");
testParse("abc123");
*/
//创建对象 var o = new Object();
//o.field = value,假如field本来不存在”类“中,会改变本对象”类“的field
//但是不会改变其他对象的field.
function Student(name,age,grade) {
this.name = name;
this.age = age;
this.grade = grade;
}
var s1 = new Student("刘胜",21,0902);
alert(s1.name + " " + s1.age + " " + s1.grade);
var s2 = new Student("小红",21,0000);
s2.class = 7;
//alert(s2.name + " " + s2.age + " " + s2.grade);
alert(s2.class);
</script>
精通JavaScript前70面总结
最新推荐文章于 2025-08-21 23:22:44 发布