JavaScript substr () string intercept function using detailed

SUBSTR Definition and usage
The substr () method extracts a specified number of characters from the start subscript in a string.

Grammar
Stringobject.substr (Start,length)

If length is 0 or negative, an empty string is returned. If this argument is not specified, the substring continues to the end of the stringvar.

Example
The following example demonstrates the use of the Substr method.

1. Intercepts the first character of the string.

<script type= "Text/javascript" >
var str= "jb51";
Alert (STR.SUBSTR (0,1));
</script>

The input result is J

2. Intercept the string starting with the 12th character, 5 lengths

<script type= "Text/javascript" >
function Substrdemo () {
var s, SS; Declares a variable.
var s = "The rain in Spain falls mainly in the plain.";
SS = S.substr (12, 5); Gets a substring.
return (SS); Returns "Spain".
}
Alert (Substrdemo ());
</script>

Input result is Spain

3. Use substr () to extract some characters from the string:

1)

<script type= "Text/javascript" >
var str= "Hello world!"
document.write (STR.SUBSTR (3))
</script>

The input result is Llo world!

2)

<script type= "Text/javascript" >
var str= "Hello world!"
document.write (Str.substr (3,7))
</script>

The input result is lo worl

JavaScript substr () string intercept function using detailed