How to check if an object with an ID already exists on the page? [duplicate]

问题

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Closed 8 years ago.

Possible Duplicate:
Is there an “exists” function for jQuery

Say for instance you have the div:

<div id="hello"></div>

And you are dynamically creating a div:

<div id="hello"></div>

Is there a function you can use in Jquery which will check to see if the object with the ID you are trying to create already exists on the page?

回答1:

For jQuery method you could go with

if($("#selector").length) {
    //object already exists
}

回答2:

if (document.getElementById('hello')) {
    // yup, already there
}

Or, the jQuery way:

if ($('#hello').length) {
    // yup, already there
}

来源：https://stackoverflow.com/questions/6052872/how-to-check-if-an-object-with-an-id-already-exists-on-the-page