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IF
if (condition)
{
code to be executed if condition is true
}
{
code to be executed if condition is true
}
Switch:
switch(n)
{
case 1:
execute code block 1
break
case 2:
execute code block 2
break
default:
code to be executed if n is
different from case 1 and 2
}
{
case 1:
execute code block 1
break
case 2:
execute code block 2
break
default:
code to be executed if n is
different from case 1 and 2
}
For:
for (var=startvalue;var<=endvalue;var=var+increment)
{
code to be executed
}
{
code to be executed
}
For...in:
for (variable in object)
{
code to be executed
}
{
code to be executed
}
Ví dụ:
<script type="text/javascript">
var x
var mycars = new Array()
mycars[0] = "Saab"
mycars[1] = "Volvo"
mycars[2] = "BMW"
for (x in mycars)
{
document.write(mycars[x] + "<br />")
}
</script>
var x
var mycars = new Array()
mycars[0] = "Saab"
mycars[1] = "Volvo"
mycars[2] = "BMW"
for (x in mycars)
{
document.write(mycars[x] + "<br />")
}
</script>
while:
while (var<=endvalue)
{
code to be executed
}
{
code to be executed
}
break: ngắt vòng lặp và thực hiện tiếp những script phía sau vòng lặp
Ví dụ:
<script>
n = 0;
for(i=0;i<5;i++){
if(i==2) break;
n++;
document.write('value: '+ n +'<br />');
}
n = n +10;
document.write('Value: '+n);
</script>
n = 0;
for(i=0;i<5;i++){
if(i==2) break;
n++;
document.write('value: '+ n +'<br />');
}
n = n +10;
document.write('Value: '+n);
</script>
Kết quả:
value: 1
value: 2
Value: 12
continue: bỏ qua bước lặp hiện tại và thực hiện bước lặp tiếp theo
Ví dụ:
<script>
n = 0;
for(i=0;i<5;i++){
if(i==2) continue;
n = i;
document.write('value: '+ n +'<br />');
}
n = n +10;
document.write('Value: '+n);
</script>
n = 0;
for(i=0;i<5;i++){
if(i==2) continue;
n = i;
document.write('value: '+ n +'<br />');
}
n = n +10;
document.write('Value: '+n);
</script>
Kết quả:
value: 0
value: 1
value: 3
value: 4
Value: 14
with:
Ví dụ:
<script>
with (document)
{
for (i in this)
{
write("Property = " + i + " Value = " + document[i] + "<BR>\n")
}
}</script>
with (document)
{
for (i in this)
{
write("Property = " + i + " Value = " + document[i] + "<BR>\n")
}
}</script>
Kết quả:
Property = getInterface Value = undefined
Property = console Value = undefined
................
Tác giả:TG
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