Embedded forms are not shown on my website

I tried to use IFRAME but it doesn't work. You can see on the site http://www.mspevents.nl/#xl_xr_page_boekingsformulier

what I mean. The forms are on the site but are not steady!

There are 5 forms embedded on the webpage you provided and some of them are embedded twice. All of them are embedded with the script embed code. 

Most likely there are some script conflicts between your website scripts and JotForm scripts. Please re-embed all of your forms with the iFrame code.