Alternative to trycatch for checking if a function exists in javascript - Stack Overflow

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The following statement is used because the method in question (refreshPartyList()) may not always be defined.

try {
  parent.document.getElementById("myId").contentWindow.refreshPartyList(param1, param2);
}catch(e){}

Currently using the above approach and it is working fine, but is there a better alternative?

The following statement is used because the method in question (refreshPartyList()) may not always be defined.

try {
  parent.document.getElementById("myId").contentWindow.refreshPartyList(param1, param2);
}catch(e){}

Currently using the above approach and it is working fine, but is there a better alternative?

• javascript
• try-catch

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3 Answers 3

Sorted by: Reset to default 4

var e = parent.document.getElementById("myId").contentWindow;
if(e.refreshPartyList)
  e.refreshPartyList(param1, param2);

You can check if the method exists with a simple if:

   if (parent.document.getElementById("myId").contentWindow.refreshPartyList) {
       parent.document.getElementById("myId").contentWindow.refreshPartyList(param1, param2);
   }

Or better still, with jQuery (because the if does not guarantee it is a function):

   if (jQuery.type(parent.document.getElementById("myId").contentWindow.refreshPartyList) == 'function') {

var win = parent.document.getElementById("myId").contentWindow;
win.refreshPartyList && win.refreshPartyList(param1, param2);

Use x.method && x.method(...) to check whether the method exists.

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