提交按钮在Bootstrap表单中不起作用

Question

首先，我检查了类似的帖子，但没找到我需要的答案。我无法弄清楚这里有什么问题。我在分离的文件中使用相同的表单html代码和javascript，它工作正常，但当我将这些代码集成到我的引导程序页面时，没有任何事情发生。

var count = 2;

function validate() {
    var un = document.myform.username.value;
    var pw = document.myform.pword.value;
    var valid = false;

    var unArray = ["Philip", "George", "Sarah", "Michael"];
    var pwArray = ["Password1", "Password2", "Password3", "Password4"];

    for (var i=0; i <unArray.length; i++) {
        if ((un == unArray[i]) && (pw == pwArray[i])) {
        valid = true;
        break;
        }
    }

    if (valid) {
        alert ("Login was successful");
        window.location = "http://www.google.com";
        return false;
    }

    var t = " tries";
    if (count == 1) {t = " try"}

    if (count >= 1) {
        alert ("Invalid username and/or password.  You have " + count + t + " left.");
        document.myform.username.value = "";
        document.myform.pword.value = "";
        setTimeout("document.myform.username.focus()", 25);
        setTimeout("document.myform.username.select()", 25);
        count --;
    }
    else {
        alert ("Still incorrect! You have no more tries left!");
        document.myform.username.value = "No more tries allowed!";
        document.myform.pword.value = "";
        document.myform.username.disabled = true;
        document.myform.pword.disabled = true;
        return false;
    }
}

<!-- LOGIN MODAL -->
<div class="modal fade" id="login" role="dialog">
    <div class="container">
        <div class="modal-dialog">
            <div class="row" style="margin-top:20px">
                <div class="col-md-12">
                    <div class="well well-sm">
                        <form name="myform">
                            <h2>Please Login</h2>

                            <div class="form-group">
                                <input type="text" name="username" class="form-control input-lg" placeholder="Username">
                            </div>
                            <div class="form-group">
                                <input type="password" name="pword" class="form-control input-lg" placeholder="Password">
                            </div>

                            <div class="row">
                                <div class="col-xs-12 col-md-6">
                                    <input type="submit" class="btn btn-lg btn-primary" value="Sign In" onclick="validate()">
                                </div>
                            </div>
                        </form>
                    </div>
                </div>
            </div>
        </div>
    </div>
</div>
<!-- END of LOGIN MODAL -->