<html>
<head>
<script>
function a(){
var a=prompt()
var op=prompt()
var b=prompt()
var c=0
switch(op){
case '+':c=parseInt(a)+parseInt(b);
break;
case '-':c=parseInt(a)-parseInt(b);
break;
case '*':c=parseInt(a)*parseInt(b);
break;
case '/':c=parseInt(a)/parseInt(b);
break;
}
alert(c)
}
</script>
</head>
<body>
<input type='button' value='click'
onclick='a()'/>
</body>
</html>
<html>
<head>
<script>
function a(){
var s='I am a student.student'
alert(s.length)
}
</script>
</head>
<body>
<input type='button' value='click'
onclick='a()'/>
</body>
</html>
<html>
<head>
<script>
function a(){
var s='I am a student. student'
var c=s.split(' ')
alert(c.length)
}
</script>
</head>
<body>
<input type='button' value='click'
onclick='a()'/>
</body>
</html>
<html>
<head>
<script>
function a(){
var s='3!6!5!9!2!1'
var A=s.split('!')
var s=A.slice(1,4)
var c=s.sort()
var z=c.reverse()
var b=z.join('$')
alert(b)
alert(b.indexOf('$6')!=-1)
}
</script>
</head>
<body>
<input type='button' value='click'
onclick='a()'/>
</body>
</html>
<html>
<head>
<script>
function html(){
alert('I am html')
}
function pdf(){
alert('I am html')
}
function a(){
var s='a.html'
var i=s.lastIndexOf('.')
var c=s.substring(i+1)
switch(c){
case 'html':html();break;
case 'pdf':pdf();break;
}
//aa=s.split('.')
//s1=aa[-1]
}
</script>
</head>
<body>
<input type='button' value='click'
onclick='a()'/>
</body>
</html>
<html>
<head>
<script>
function a(){
var A=[3,6,5,9,2,1]
var s=A.slice(1,4)
var c=s.sort()
var z=c.reverse()
var b= z.join('#')
alert(b)
}
</script>
</head>
<body>
<input type='button' value='click'
onclick='a()'/>
</body>
</html>
