This one's really easy!

s t e p - o n e :

Open Pixlr. Create a blank canvas or load your current one.

s t e p - t w o :

Click the Text Tool. Type whatever you want and use any font - I suggest a bolder one. Make sure it's what you want because you won't be able to go back and change it unless you start over!

s t e p - t h r e e :

Right click on the Text layer and press "Rasterize layer". This will make it editable.

s t e p - f o u r :

Go up to "Edit" and press "Select Pixels". This will select your text.

s t e p - f i v e :

Next, go to the Gradient Tool. This is under the Eraser.

s t e p - s i x :

Go up to the top and choose whatever colors you want your stripes to be.

s t e p - s e v e n :

Look at the top for "Spread method". Press the drop down and change it to "Repeat".

s t e p - e i g h t :

Make a short horizontal line. The shorter you make it, the closer together the stripes are. Keep doing it until it has your desired look.

s t e p - n i n e :

Deselect. Press CTRL+D or Command+D, or manually deselect by going to "Edit" and "Deselect all".

That's it!