click() with links

问题

I have a page with a few links that are all like this:

<a href="/" class="answer-item" rel="0">10</a>

I would like to use the click() function to simulate a user's click on one of them, but it doesn't seem to work in my tests.

//Evaluate a mathematical expression from another part of the page
var numberAnswer = eval(document.getElementById("question-title").getElementsByTagName("b")[0].innerHTML);

//Builds an array with the links that may match the expression
var choices = document.getElementsByClassName('answer-item');

//Iterates through array to find a match then clicks it
for(var i in choices){
    if(choices[i].innerHTML == numberAnswer){
        choices[i].click();
        break;
    }
}

I'm sure that choices[i] is the correct element.

Firefox does nothing, Opera does nothing, and click() is not available in Chrome (I think).

Also, I have tried to use dispatchEvent() in this form:

var evt = document.createEvent('MouseEvents');
evt.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
choices[i].dispatchEvent(evt);

This apparently returned true in Firefox and Chrome but did not change anything.

The most bothersome part is that a link with only the href attribute works fine with .click().

回答1:

EDIT

Per discussion in the comment area, it seems that the behavior used in this answer is non-standard, or at least not consistent across user-agents. I am researching this issue further; if you use the information in this answer, please carefully check your code in all browsers to ensure it works as expected.

---

EDIT 2

Per the comment from the OP, there is a "just make it happen" approach that would work here. It has some downsides, namely that your bound events cannot call preventDefault -- this method will not respect it. You could build some kind of event wrapper that might be able to deal with this... anyway, here's the code and fiddle:

HTML:

<br><br>
<!-- I am totally misusing this API! -->
<a href="http://jsfiddle.net/echo/js/?delay=0&js=The link was followed;" id="progra_link">Some link with an event that uses preventDefault()</a>
<br><br>
<button id="doit_btn">Programmatically click the link</button>

Script:

function do_program_click () {
    var lnk = document.getElementById('progra_link');
    var loc = lnk.href;
    if (!loc)
        return false;            
    // call this to fire events
    lnk.click();

    // then follow the link
    document.location = loc;
    return;
};
function addEvent(element, evnt, funct){
  if (element.attachEvent)
   return element.attachEvent('on'+evnt, funct);
  else
   return element.addEventListener(evnt, funct, false);
}

// bind an event to the link to test force event trigger
addEvent(
    document.getElementById('progra_link'),
    'click',
    function (e) {
        e.preventDefault();
        alert('Testing element click event, default action should have been stopped');
        return false;
    }
);
// bind event to the leeroy button
addEvent(
    document.getElementById('doit_btn'),
    'click',
    do_program_click
);

jsFiddle: http://jsfiddle.net/CHMLh/

---

Original answer

Your sample code is incomplete. If I take just the basics, it works correctly:

<script>
   var lnk = document.getElementById('test');
   lnk.click();
</script>
<a id="test" href="/" class="answer-item" rel="0">test link</a>

jsFiddle: http://jsfiddle.net/cgejS/

I would re-evaluate your assumptions that you're dealing with the correct dom element.

On an unrelated note, this:

var numberAnswer = eval(document.getElementById("question-title").getElementsByTagName("b")[0].innerHTML);

... what? eval is evil -- if you're ever using it for any reason, question whether you have the right approach. Are you trying to get an integer out of a string? See parseInt (docs), the right tool for this job:

// this line is still failure-prone...
var ele = document.getElementById("question-title").getElementsByTagName("b")[0];
var numberAnswer = 0;
if (ele)
   numberAnswer = parseInt(ele.innerHTML);

回答2:

Easy.

The HTML (note that I added an 'id' tag):

<a id="answer-item" href="/" class="answer-item" rel="0">10</a>

The JS:

document.getElementById('answer-item').click();

来源：https://stackoverflow.com/questions/10000852/click-with-links