len and left functions in vbscript

The Left function returns a specified number of characters from the left side of a string.

Tip: Use the Len function to find the number of characters in a string.

Tip: Also look at the Right function.
Syntax
Left(string,length)

Parameter Description
string Required. The string to return characters from
length Required. Specifies how many characters to return. If set to 0, an empty string ("") is returned. If set to greater than or equal to the length of the string, the entire string is returned

Example 1
txt="This is a beautiful day!"
document.write(Left(txt,15))

output:
This is a beaut

Example 2
txt="This is a beautiful day!"
x=Len(txt)
document.write(Left(txt,x))

output:
This is a beautiful day!