1：html注释：
<html> <body> <script type="text/javascript"> <!-- document.write("Hello World!"); //两个正斜杠是 JavaScript 的注释符号，它会阻止 JavaScript 编译器对这一行的编译--> </script> </body> </html>
2：支持三元运算符
greeting=(visitor=="PRES")?"Dear President ":"Dear ";
3：三种消息框
警告框：alert("text")
确认框：confirm("text")
提示框：prompt("noon",12)
4：类似python的for in
var x var mycars = new Array() mycars[0] = "Saab" mycars[1] = "Volvo" mycars[2] = "BMW" for (x in mycars) { document.write(mycars[x] + "<br />") }
5：异常处理
<html> <body> <script type="text/javascript"> while(true){ var x=prompt("Enter a number between 0 and 10:","") try { if(x>10) throw "Err1" else if(x<0) throw "Err2" else break } catch(er) { if(er=="Err1") alert("Error! The value is too high") if(er == "Err2") alert("Error! The value is too low") }} </script> </body> </html
6：显示时间
<html> <head> <script type="text/javascript"> function startTime() { var today=new Date() var h=today.getHours() var m=today.getMinutes() var s=today.getSeconds() // add a zero in front of numbers<10 m=checkTime(m) s=checkTime(s) document.getElementById(‘txt‘).innerHTML=h+":"+m+":"+s t=setTimeout(‘startTime()‘,500) } function checkTime(i) { if (i<10) {i="0" + i} return i } </script> </head> <body onload="startTime()"> <div id="txt"></div> </body> </html>