Just like your other two functions, you'll need to use nested loops for your DOM function.
Something that needs some attention aswell is:
<input type="button" value="DOM" onclick="DOM(Table)">
Furthermore you should take a look at your variable declerations aswell. You're creating alot of global variables, where you should use locals.
Using more descriptive variable names will make your code easier to read. It's a bit more typing, but if you use alot of variables it might get hard to remember the difference between a lower- and a uppercase 'r'.
In the 'dwrite' function, for(i=1;i<=r;i++) will create variable 'i' in the global scope. In the 'multiplier' you do it right, using the 'var' keyword.
In the 'multiplier' function, r, c, x, i, j are declared local. But you don't declare 'I' as a local variable, so 'I' becomes unnecessary a global.
In the DOM you create alot of global variable, which should be local variable aswell.