Date: 2009nov9
Language: javaScript
Platform: web
Q. javaScript: How can I check if a function exists (without an error message) ?
A. Top level function are created in the window object so you can do:
if (window.myFunc) {
// Function exists so call it
myFunc()
}
You can construct the function name too. For example:
let myFunc = doSomeThingToMakeTheNameOfTheFunction();
if (window[myFunc]) {
// Function exists so call it
window[myFunc]();
}
For example, dump() exists in Firefox but not IE. So we made
a function called debug() that calls the first function:
function debug(a) {
if (window.dump) {
dump(a);
}
else if (window.console && window.console.log) {
window.console.log(a);
}
}