My iPhone 4 won't charge using USB cord?

My iPhone won't charge using the usb cord connected to the wall or laptop but it will charge on the dock of my radio, what's wrong?

Added (1). The usb cord works for other apple products

The usb cord is corroded.

  • Why won't my iphone usb cord work? I have a charger for my iphone, the part that plugs into the wall is separate from the usb cord the cord isn't charging my phone, i know its the cord bc i've tried my friends, but i obviously can't keep them my phone charges in the doc so what do you think i did to my usb cord to make it not work, it just stopped working one day like i don't understand
  • Where can I buy a cheap iphone usb cord? I lost mine and my phone is almost dead I need one today but I don't want to get one from Apple cause they're $20, I could get for $1.50 from Amazon but then I'd have to wait for it to ship Are there any stores that sell cheap ones?
  • What happens to iPhone if USB cord wasn't fully plugged into phone? I often leave my iphone to charge overnight but recently I woke up and the phone said it was charging but it was at 10%. On further inspection, I saw that the USB cord was like half way into the power adapter. Is this damaging to the battery? I'm worried that my new 5S is damaged because the battery seems to drain about 10% faster.
  • My iphone won't connect to anything via USB cord I was using my phone connected to my computer via USB cord then i took it out for a little while then tried to put it back it and it isn't working! I tried 2 different cables plugged into my computer and charger but nothing works. The phone won't connect.anyone know what's wrong?