Setting maxlength of textbox with JavaScript or jQ

问题:

I want to change the maxlength of a textbox with JavaScript or jQuery: I tried the following but it didn't seem to help:

var a = document.getElementsByTagName('input');
for(var i=0; i<a.length; i++) {
    if((a[i].type!= 'radio')||(a[i].type!= 'checkbox'))
        a[i].maxlength = 5;
}
document.getElementsByTagName('input')[1].maxlength="3";

$().ready(function()
{
    $("#inputID").maxlength(6);
});

What am I doing wrong?

回答1:

Not sure what you are trying to accomplish on your first few lines but you can try this:

$(document).ready(function()
{
    $("#ms_num").attr('maxlength','6');
});

回答2:

The max length property is camel-cased: maxLength

jQuery doesn't come with a maxlength method by default. Also, your document ready function isn't technically correct:

$(document).ready(function () {
    $("#ms_num")[0].maxLength = 6;
    // OR:
    $("#ms_num").attr('maxlength', 6);
    // OR you can use prop if you are using jQuery 1.6+:
    $("#ms_num").prop('maxLength', 6);
});

Also, since you are using jQuery, you can rewrite your code like this (taking advantage of jQuery 1.6+):

$('input').each(function (index) {
    var element = $(this);
    if (index === 1) {
        element.prop('maxLength', 3);
    } else if (element.is(':radio') || element.is(':checkbox')) {
        element.prop('maxLength', 5);
    }
});

$(function() {
    $("#ms_num").prop('maxLength', 6);
});

回答3:

set the attribute, not a property

$("#ms_num").attr("maxlength", 6);

回答4:

without jQuery you can use

document.getElementById('text_input').setAttribute('maxlength',200);

回答5:

$('#yourTextBoxId').live('change keyup paste', function(){
    if ($('#yourTextBoxId').val().length > 11) {
        $('#yourTextBoxId').val($('#yourTextBoxId').val().substr(0,10));
    }
});

I Used this along with vars and selectors caching for performance and that did the trick ..

回答6:

You can make it like this:

$('#inputID').keypress(function () {
    var maxLength = $(this).val().length;
    if (maxLength >= 5) {
        alert('You cannot enter more than ' + maxLength + ' chars');
        return false;
    }
});

回答7:

How about just maxlength="10"? For example,

<input type="text" maxlength="10">