JavaScript
- Comparison Operators
Operator Description Example == is equal to 5==8 returns false === is equal to (checks for both value and type) x=5
y="5"x==y returns true
x===y returns false
- Conditional Operator
Syntax
variablename=(condition)?value1:value2
Example
greeting=(visitor=="PRES")?"Dear President ":"Dear "
- Confirm Box
<script type="text/javascript">
function disp_confirm()
{
var r=confirm("Press a button")
if (r==true)
{
document.write("You pressed OK!")
}
else
{
document.write("You pressed Cancel!")
}
}
</script>
- Prompt Box
<script type="text/javascript">
function disp_prompt()
{
var name=prompt("Please enter your name","Harry Potter")
if (name!=null && name!="")
{
document.write("Hello " + name + "! How are you today?")
}
}
</script>
- Break
Example
<script type="text/javascript">
var i=0
for (i=0;i<=10;i++)
{
if (i==3){break}
document.write("The number is " + i)
document.write("<br />")
}
</script>
Result
The number is 0
The number is 1
The number is 2 - Continue
Example
<script type="text/javascript">
var i=0
for (i=0;i<=10;i++)
{
if (i==3){continue}
document.write("The number is " + i)
document.write("<br />")
}
</script>
Result
The number is 0
The number is 1
The number is 2
The number is 4
The number is 5
The number is 6
The number is 7
The number is 8
The number is 9
The number is 10