Help required with javascript code

[trb1975]

Hi, I am hoping someone would give me a few minutes with the following. I have the task of translating some javascipt into Visual Basic. Unfortunately my knowledge of Javascript is pretty poor and I am having difficulty in working out what the javascript code is doing. The code is as follows :

================================================

acc=0
i=1
for (i = 1; i <= 8; i++) {
if (i > 1) {
cy = (acc & 7) * 8192
cy = cy % 65536
acc = pInt(acc/8) | cy
}
if (pdte.substring(i-1,i)=="/") {
acc = acc + 47
}
else {
acc = acc + 48 + (pdte.substring(i-1,i)*1)
}
acc = acc % 65536
}
return acc % pmod
}
function pInt(piwork)
{
var y
y = piwork + " "
if (y.indexOf(".") != -1)
{
return y.substr(0,y.indexOf(".")) * 1
}
return piwork
}
=============================================

For info pdte would be a date - i.e. 01/01/06

The parts I am having dificulty understanding are :

cy = (acc & 7) * 8192 (What does acc & 7) do ??

acc = pInt(acc/8) | cy (What does the pInt function return - is it for example : if 1234.9999 is passed to it does it return 1234??? Also what does the | cy do??

Are the substrings only passing one back one character each time??


I just need to know what these do so that I can use the VB equivalent.

Many Thanks
Tony

[ukgeoff]

(acc & 7) is a bitwise AND.

The % symbol is for modulus, i.e., a % b returns the integer remainder of a div b.

the substring function returns a substring whose length is determined by it two parameters. As in this case you are using i-1 and i, you are effectively retrieving a single character starting from position i-1. Remember string positions start from 0.

This next bit is a combination of normal sums and bitwise again. (acc / 8) | cy is the result of acc divided by 8 and then OR'ed with cy.

As far as I can see, the purpose of pInt is to return the integer part of a decimal number.