html - I want to change the look of my donate button -

on website creating use bootstrap button btn-primary, donate button instead of 1 offered paypal. problem when attempt change button, button no longer works.

here working piece of code:

<div id="donate-button-image">   <input type="image"    src="https://www.paypalobjects.com/en_us/i/btn/btn_donatecc_lg.gif"    border="0" name="submit" onclick="calculateorder(this.form)"> </div> 

when change second line input type button instead of image, , change src class can specify want btn-primary, onclick function stops working, seen below

<div id="donate-button-image">   <input type="button" class="btn btn-primary" border="0"    name="submit"onclick="calculateorder(this.form)"> </div> 

with paypal button, taken paypal page donate, after changing it, button has no function. don't how changing more style of button? appreciated, thank you!

here javascript:

function calculateorder(form){  var radg1;  var totalamount=0;  (var = 0; < document.myform.os0.length; i++){  if(document.myform.os0[i].checked==true){    radg1=document.myform.os0[i].value;}     }  if(radg1 == "5.00"){   document.myform.amount.value = '5.00';   document.myform.item_number.value = "wf-5-00";   }  else if(radg1 == "10.00"){   document.myform.amount.value = '10.00';   document.myform.item_number.value = "wf-10-00";   }  else if(radg1 == "25.00"){   document.myform.amount.value = '25.00';   document.myform.item_number.value = "wf-25-00";   }  else if(radg1 == "50.00"){  document.myform.amount.value = '50.00';  document.myform.item_number.value = "wf-50-00";   }   else if(radg1 == "other"){   document.myform.amount.value = '0.00';   document.myform.item_number.value = "wf-0-00";   }   }