Question

我想使用这个jquery插件，但我无法进行空字段验证。我有一个表格，想在提交表格之前检查空白字段。我只是给了选择框一个名称属性title，并将下面的代码用于检查我认为永远不会起作用的内容。

<script type="text/javascript">
if(title == "")
{
$('#hm_system_status_message').html('<div class="hm_error_info" align="left">Please enter Title in the required field to proceed. Thanks.</div>');
$("#hm_title").focus();

}，

它没有用，所以如何检查空字段并显示错误消息？我不想使用弹出错误消息，只是组合框旁边显示的消息。请帮忙。

<!doctype html>

<html lang="en">
<head>
<meta charset="utf-8" />
<title>jQuery UI Autocomplete - Combobox</title>
<link rel="stylesheet" href="http://code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css" />
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>
<link rel="stylesheet" href="/resources/demos/style.css" />
<style>
.custom-combobox {
    position: relative;
    display: inline-block;
}
.custom-combobox-toggle {
    position: absolute;
    top: 0;
    bottom: 0;
    margin-left: -1px;
    padding: 0;
    /* support: IE7 */
    *height: 1.7em;
    *top: 0.1em;
}
.custom-combobox-input {
    margin: 0;
    padding: 0.3em;
}
</style>
<script>
(function( $ ) {
    $.widget( "custom.combobox", {
        _create: function() {
            this.wrapper = $( "<span>" )
                .addClass( "custom-combobox" )
                .insertAfter( this.element );

            this.element.hide();
            this._createAutocomplete();
            this._createShowAllButton();
        },


        _createAutocomplete: function() {
            var selected = this.element.children( ":selected" ),
                value = selected.val() ? selected.text() : "";

            this.input = $( "<input>" )
                .appendTo( this.wrapper )
                .val( value )
                .attr( "title", "" )
                .addClass( "custom-combobox-input ui-widget ui-widget-content ui-state-default ui-corner-left" )
                .autocomplete({
                    delay: 0,
                    minLength: 0,
                    source: $.proxy( this, "_source" )
                })
                .tooltip({
                    tooltipClass: "ui-state-highlight"
                });

            this._on( this.input, {
                autocompleteselect: function( event, ui ) {
                    ui.item.option.selected = true;
                    this._trigger( "select", event, {
                        item: ui.item.option
                    });
                },

                autocompletechange: "_removeIfInvalid"
            });
        },

        _createShowAllButton: function() {
            var input = this.input,
                wasOpen = false;

            $( "<a>" )
                .attr( "tabIndex", -1 )
                .attr( "title", "Show All Items" )
                .tooltip()
                .appendTo( this.wrapper )
                .button({
                    icons: {
                        primary: "ui-icon-triangle-1-s"
                    },
                    text: false
                })
                .removeClass( "ui-corner-all" )
                .addClass( "custom-combobox-toggle ui-corner-right" )
                .mousedown(function() {
                    wasOpen = input.autocomplete( "widget" ).is( ":visible" );
                })
                .click(function() {
                    input.focus();

                    // Close if already visible
                    if ( wasOpen ) {
                        return;
                    }

                    // Pass empty string as value to search for, displaying all results
                    input.autocomplete( "search", "" );
                });
        },

        _source: function( request, response ) {
            var matcher = new RegExp( $.ui.autocomplete.escapeRegex(request.term), "i" );
            response( this.element.children( "option" ).map(function() {
                var text = $( this ).text();
                if ( this.value && ( !request.term || matcher.test(text) ) )
                    return {
                        label: text,
                        value: text,
                        option: this
                    };
            }) );
        },

        _removeIfInvalid: function( event, ui ) {

            // Selected an item, nothing to do
            if ( ui.item ) {
                return;
            }

            // Search for a match (case-insensitive)
            var value = this.input.val(),
                valueLowerCase = value.toLowerCase(),
                valid = false;
            this.element.children( "option" ).each(function() {
                if ( $( this ).text().toLowerCase() === valueLowerCase ) {
                    this.selected = valid = true;
                    return false;
                }
            });

            // Found a match, nothing to do
            if ( valid ) {
                return;
            }

            // Remove invalid value
            this.input
                .val( "" )
                .attr( "title", value + " didn't match any item" )
                .tooltip( "open" );
            this.element.val( "" );
            this._delay(function() {
                this.input.tooltip( "close" ).attr( "title", "" );
            }, 2500 );
            this.input.data( "ui-autocomplete" ).term = "";
        },

        _destroy: function() {
            this.wrapper.remove();
            this.element.show();
        }
    });
})( jQuery );

$(function() {
    $( "#combobox" ).combobox();
    $( "#toggle" ).click(function() {
        $( "#combobox" ).toggle();
    });
});

</script>
<script type="text/javascript">
if(title == "")
{
    $('#hm_system_status_message').html('<div class="hm_error_info" align="left">Please enter Title in the required field to proceed. Thanks.</div>');
    $("#hm_title").focus();
},
</script>
  </head>
   <body>
    <form action="test.php" method="post">
    <div class="ui-widget">
<label>Your preferred programming language: </label>
<select name="title" id="combobox">
    <option value="">Select one...</option>
    <option value="ActionScript">ActionScript</option>
    <option value="AppleScript">AppleScript</option>
    <option value="Asp">Asp</option>
    <option value="BASIC">BASIC</option>
    <option value="C">C</option>
    <option value="C++">C++</option>
    <option value="Clojure">Clojure</option>
    <option value="COBOL">COBOL</option>
    <option value="ColdFusion">ColdFusion</option>
    <option value="Erlang">Erlang</option>
    <option value="Fortran">Fortran</option>
    <option value="Groovy">Groovy</option>
    <option value="Haskell">Haskell</option>
    <option value="Java">Java</option>
    <option value="JavaScript">JavaScript</option>
    <option value="Lisp">Lisp</option>
    <option value="Perl">Perl</option>
    <option value="PHP">PHP</option>
    <option value="Python">Python</option>
    <option value="Ruby">Ruby</option>
    <option value="Scala">Scala</option>
    <option value="Scheme">Scheme</option>
</select><br>
<input type="submit" value="submit">

Answer 1

您可以像这样使用jquery

var value = $('#city').val();
if (value == -1) 
{
   alert('select combo value');
   return false;
}
else 
{
  return true;
}

您可以将索引0或-1指定给组合框的选择选项

<option value="-1">Select one...</option>

愿这对你有所帮助。

Answer 2

您不能将name属性用作变量，您可以使用id属性。

<script>
if (title.value == "") {
   // do your stuff
}
</script>

jQuery组合框验证

2 个答案: