escape new line character

escape new line character

Hi,
I would like to check if a string contains a \ character (backslash)
I try this:

    if ((input.invoer).indexOf("\")  >  0)
    {
        found = true;
    }

But the I get the error:

Error at line xx : Script contains new line character, kindly remove it and try again.

I have tried ("\\") but that doesn't work
So how do I do this?