How to delete this in Illustrator?

Hello everyone I need some help in Illustrator. I want to delete the thing which goes beyond the layer rectangle, I want it only inside the rectangle.Attachment 100835

How can I do this? Thank you.

Using the pen tool, hit the plus key to the right of the backspace key (not the plus key on a num pad), add nodes to the blue curve where it crosses the green rectangle at the top and bottom.

Delete the nodes extending above and below the green rectangle by pressing the minus key (again, the minus key to the left of the backspace key, not the minus key on the numpad). This will leave you with just the nodes at the top and bottom of the green rectangle but there will likely be a curved segment above/below the green rectangle because these will still be smooth curve nodes.

Switch the the white pointer. Hold the alt key down and adjust the handles which will convert the nodes to corner nodes and allow you to adjust the curved portion at the same time.

Mike

Thank you mwenz, but there's a problem. I've maded this rectangle tool with arc effect now It's kinda hard to correct this look. Is there any other way to make arc effect? Thank you Attachment 100838

However you did it at the top, do it at the bottom...But not knowing exactly how it is constructed, in general try the Expand and/or the Expand Appearance command(s) from the Object menu.

Failing that working, if you upload your file, I can take a look. You may have to ZIP it in order to attach it.

Here's the test file attached. Please take a look. I know quite allot Photoshop, but I really sux at Illustrator. Hate everything in Illustrator, other shortcuts etc. Need to get used to it ;). Take a look, thank you for your help.

You did get close.

Like I mentioned, select the curved part. then from the Object Menu, select Expand Appearance.

In the screen shot, I dragged two guides down to the top and bottom of the rectangle.

Select the white pointer (Direct Selection Tool). Zoom in close to one of the corners. Click once on the node you zoomed in on. Move the node onto the guide. Turning on Smart Guides might also help. Now notice that the top extended handle that controls the curve is above the line (if you are working on the top part first). Click on it still using the white pointer. Move the handle straight down onto the guide and it should lightly snap to it. Do the other corner. Move to the other end and do it as well.

Attachment 100842

Attachment 100843

Mike has given you great information and showed you how to achieve your shape, can I change the direction slightly. In my opinion your problem has arisen out of not using the Pen Tool to do the job. The Pen Tool is the backbone of Illustrator and is the most used tool on a day to day basis and to not use this tool is going to stop your development in AI. Now I would normally post my own version of this but at the 2 weeks ago I had an SSD disc failure and I have not got my files back in the right directories so I have lifted this directly from Vector Tuts.
Start a new doc (Ctrl+N), Place this file into your doc and then lock that layer, Make a New Layer in the Layer palette - this is the drawing layer. Now this is a large bitmap which I have reduced down and can be found here with a few other ex. that you might want to try: http://southeastcc.files.wordpress.c..._exercise1.jpg

The attached file is not good quality so go to the supplied web address and download it to your computer. There is a lot of help here and throughout the net so don't be afraid to ask. If you want to use Illy you are going to have to learn how to use the Pen Tool.