Javascript尝试捕获DIV

Question

I am trying to build a catch try to execute some javascript code. NO JQUERY I want to identify if a div id ('test') exists and if it doesn't don't execute the code. How would I do this? I know the structure of a try catch is

try{

}
catch(e){

}

Answer 1

use try-catch as less as possible: just check whether or not the DOM element exists:

if (document.getElementById('test')!=null) {
    // element (div) with id 'test' exists
}
else {
    // it doesn't
}

Answer 2

I would make things simpler and use if instead of try-catch . try-catch is designed for exceptional situations, when you really don't know what to do throw an error. Throwing an error causes the whole code block to terminate it's execution.

I would do like this:

var divId = 'test';

if (document.getElementById(divId)) {
    alert('exists');
} else {
    alert('does not exist');
}

There is no need to check document.getElementById() result on null (in all modern browsers null is returned when no element is found). In most JavaScript projects developers skip typing !== null since null is treated as false and DOM object is treated as true , so programmers avoid typing obvious things.