Javascript函数在桌面上可用，在移动浏览器上失败

Question

As a rule, I post on SO only as a LAST resort, when I fail to get a solution from all other sources. I've been scratching my head over this issue for a whole day now, and considering the plight of some similar questions, I am not very hopeful that I'll get an answer this time.

Here is my humble javascript validation function which is called when a button is clicked. The buttons when clicked pass an argument ('previous' or 'next') to this function. Now trouble is, this works on all major desktop browsers I tried including IE-11 and Firefox-26. However, on ios and WP8, this function is consistently failing. Nothing happens when the button is clicked (swiped) on mobile (it should either show an alert or move to the next block). Here is the code for javascript function:

function validateForm(button){
    smand=mandatory_check();
    if (smand != ''){
        alert('The following fields are mandatory:\n\n' + smand);
        return;
    }        
    if (button=='next'){
        if (scr_curr == (scr_count)){
            smand=mandatory_check(true);
            if (smand != ''){
                alert('The following fields are mandatory:\n\n' + smand);
                return;
            }
            else
                $('#formLawsuit').submit();
        }
        else{
            $('#screen' + scr_curr).addClass('hidden');
            scr_curr+=1;
            $('#screen' + scr_curr).removeClass('hidden');              
            if (scr_curr>1)
                $('#btnPrev').removeClass('hidden');
            if (scr_curr==scr_count)
                showConfirm();
        }
    }
    else{
        $('#screen' + scr_curr).addClass('hidden');
        scr_curr-=1;
        $('#screen' + scr_curr).removeClass('hidden');
        if (scr_curr==1)
            $('#btnPrev').addClass('hidden');
    }
}
function mandatory_check(finale=false){
    var screen='';
    var s='';
    if (!finale)
        screen = '#screen' + scr_curr;
    else
        screen = '#formLawsuit';
    $(screen + ' .control-label').each(function(i) {
        var label = $(this).attr('id');
        var input = '#' + label.replace('label','input');
        //alert(input);
        if ($(input).hasClass('mandatory') && $(input).val()==''){
            s += label.replace('label','') + '\n';
        }
    }        
);
    return s;
}

And these are the two innocent html buttons that call this validate function:

<div class="form-group">
    <div  style="margin-bottom:120px;" class="col-lg-offset-2 col-lg-6" >
        <button id="btnPrev" name="btnPrev" type="button" class="hidden btn btn-primary btn-lg" onclick="javascript:validateForm('previous')">Previous</button>
        <button id="btnSubmit" name="btnPrev" type="button" class="btn btn-primary btn-lg" onclick="javascript:validateForm('next')">Next</button>
    </div>
</div>

The form and buttons are based on twitter-bootstrap, though I don't think that should make any difference to this.

Answer 1

Though I did not receive a ready-made solution to this problem, I was pointed in the right direction (all thanks to @Reigel). Hope this answer helps someone in future looking for similar problems.

There were many errors with my javascript code. Unfortunately, most desktop browsers are way too lenient to catch these and as a result we don't get them in testing. Firstly, I had two buttons with the same name attribute (I forgot to change them during the usual copy paste):

    <button id="btnPrev" name="btnPrev" type="button" class="hidden btn btn-primary btn-lg" onclick="javascript:validateForm('previous')">Previous</button>
    <button id="btnSubmit" name="btnPrev" type="button" class="btn btn-primary btn-lg" onclick="javascript:validateForm('next')">Next</button>

Whilst most browsers allow this leniently, turns out IE on WP8 doesn't allow this.

Another issue was that I forgot to place block if statements at many places. I came to know when I tested my code using http://www.javascriptlint.com/online_lint.php .

        if (scr_curr>1)
            $('#btnPrev').removeClass('hidden');
        if (scr_curr==scr_count)
            showConfirm();

After doing these changes, my web app started working fine on WP8 and ios browsers.