var.replace is not a function

I'm using the below code to try to trim the string in Javascript but am getting the error mentioned in the title:

function trim(str) {
    return str.replace(/^\s+|\s+$/g,'');
}

Edit:

I fixed the problem.... sorry I should have put the code on how I was calling it too.... realized I accidentally was passing the object of the form field itself rather than its value.

Solution 1:

My guess is that the code that's calling your trim function is not actually passing a string to it.

To fix this, you can make str a string, like this: str.toString().replace(...)
_{...as alper pointed out below.}

Solution 2:

probable issues:

• variable is NUMBER (instead of string);
  num=35; num.replace(3,'three'); =====> ERROR
num=35; num.toString().replace(3,'three'); =====> CORRECT !!!!!!
num='35'; num.replace(3,'three'); =====> CORRECT !!!!!!
• variable is object (instead of string);
• variable is not defined;