Why is programmatic click not working on IE or Chrome?

I'm using this bookmarklet to programmatically click on the search button in Google's Keyword Tool:

javascript:document.getElementById("gwt-debug-searchPanel-searchButton").click();

I also tried this in IE with no luck:

javascript:document.getElementById("gwt-debug-searchPanel-searchButto开发者_JAVA百科n").fireEvent("onclick");

It actually worked once but then it didn't work anymore. It works fine on Firefox, but not on Chrome or IE. Any idea why?

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That button is likely going to submit a form, why not submit the form with Javascript? You are always allowed to do that.