Question

我有一张表格

<div id="form-main">
      <div id="form-div">
        <form class="form" id="form1">

          <p class="name">
            <input name="name" type="text" class="validate[required,custom[onlyLetter],length[0,100]] feedback-input" placeholder="Name" id="name" />
          </p>

          <p class="email">
            <input name="email" type="text" class="validate[required,custom[email]] feedback-input" id="email" placeholder="Email" />
          </p>

          <p class="text">
            <textarea name="text" class="validate[required,length[6,300]] feedback-input" id="comment" placeholder="Comment"></textarea>
          </p>


          <div class="submit">
            <input type="submit" value="SEND" id="button-blue"/>
            <div class="ease"></div>
          </div>
        </form>
      </div>

及其css

@import url(http://fonts.googleapis.com/css?family=Montserrat:400,700);

    html{    background:url(http://thekitemap.com/images/feedback-img.jpg) no-repeat;
      background-size: cover;
      height:100%;
    }

    #feedback-page{
        text-align:center;
    }

    #form-main{
        width:100%;
        float:left;
        padding-top:0px;
    }

    #form-div {
        background-color:rgba(72,72,72,0.4);
        padding-left:35px;
        padding-right:35px;
        padding-top:35px;
        padding-bottom:50px;
        width: 450px;
        float: left;
        left: 50%;
        position: absolute;
      margin-top:30px;
        margin-left: -260px;
      -moz-border-radius: 7px;
      -webkit-border-radius: 7px;
    }

    .feedback-input {
        color:#3c3c3c;
        font-family: Helvetica, Arial, sans-serif;
      font-weight:500;
        font-size: 18px;
        border-radius: 0;
        line-height: 22px;
        background-color: #fbfbfb;
        padding: 13px 13px 13px 54px;
        margin-bottom: 10px;
        width:100%;
        -webkit-box-sizing: border-box;
        -moz-box-sizing: border-box;
        -ms-box-sizing: border-box;
        box-sizing: border-box;
      border: 3px solid rgba(0,0,0,0);
    }

    .feedback-input:focus{
        background: #fff;
        box-shadow: 0;
        border: 3px solid #3498db;
        color: #3498db;
        outline: none;
      padding: 13px 13px 13px 54px;
    }

    .focused{
        color:#30aed6;
        border:#30aed6 solid 3px;
    }

    /* Icons ---------------------------------- */
    #name{
        background-image: url(http://www.izwipe.com/change/c/data/3.gif);
        background-size: 30px 30px;
        background-position: 11px 8px;
        background-repeat: no-repeat;
    }

    #name:focus{
        background-image: url(http://www.izwipe.com/change/c/data/3.gif);
        background-size: 30px 30px;
        background-position: 8px 5px;
      background-position: 11px 8px;
        background-repeat: no-repeat;
    }

    #email{
        background-image: url(http://rexkirby.com/kirbyandson/images/email.svg);
        background-size: 30px 30px;
        background-position: 11px 8px;
        background-repeat: no-repeat;
    }

    #email:focus{
        background-image: url(http://rexkirby.com/kirbyandson/images/email.svg);
        background-size: 30px 30px;
      background-position: 11px 8px;
        background-repeat: no-repeat;
    }

    #comment{
        background-image: url(http://rexkirby.com/kirbyandson/images/comment.svg);
        background-size: 30px 30px;
        background-position: 11px 8px;
        background-repeat: no-repeat;
    }

    textarea {
        width: 100%;
        height: 150px;
        line-height: 150%;
    }

    input:hover, textarea:hover,
    input:focus, textarea:focus {
        background-color:white;
    }

    #button-blue{
        font-family: 'Montserrat', Arial, Helvetica, sans-serif;
        float:left;
        width: 100%;
        border: #fbfbfb solid 4px;
        cursor:pointer;
        background-color: #3498db;
        color:white;
        font-size:24px;
        padding-top:22px;
        padding-bottom:22px;
        -webkit-transition: all 0.3s;
        -moz-transition: all 0.3s;
        transition: all 0.3s;
      margin-top:-4px;
      font-weight:700;
    }

    #button-blue:hover{
        background-color: rgba(0,0,0,0);
        color: #0493bd;
    }

    .submit:hover {
        color: #3498db;
    }

    .ease {
        width: 0px;
        height: 74px;
        background-color: #fbfbfb;
        -webkit-transition: .3s ease;
        -moz-transition: .3s ease;
        -o-transition: .3s ease;
        -ms-transition: .3s ease;
        transition: .3s ease;
    }

    .submit:hover .ease{
      width:100%;
      background-color:white;
    }

    @media only screen and (max-width: 580px) {
        #form-div{
            left: 3%;
            margin-right: 3%;
            width: 88%;
            margin-left: 0;
            padding-left: 3%;
            padding-right: 3%;
        }
    }

当我输入一个以3开头的数字时，我想要一个图像“visa”中的图像，当我输入一个数字时我想要另一个图像9.这可能吗？

我有一个javascript

var num2img = {
  "3":"visa",
  "9":"mastercard"
};

$('#num').keyup(function(){
  var val = this.value;
  if(val.length<=1){
     var n = this.value.charAt(0);
     if(val && num2img[n]!==undefined){
       $('#cardImage')[0].src = 'http://placehold.it/100x100/eee&text='+ num2img[n] +'.png';
     }else{
       $('#cardImage')[0].src = 'http://placehold.it/100x100/cf5';
     }
  }
});

但图片是在css中给出的，所以图片没有id，这个javascript是用于html图片。有人可以帮我这么做吗？

Answer 1

您必须更改CSS属性

$('body').css('background','url(http://www.placehold.it/300x300) no-repeat top left');

看到这个小提琴：http://jsfiddle.net/qg7H6/

Answer 2

您可以像这样更改css中的网址：

$('#cardImage')[0].css("background-image", "url('http://placehold.it/100x100/eee&text='+ num2img[n] +'.png')");

Answer 3

Demo

var num2img = {
  "3":"visa",
  "9":"mastercard"
};

$('#name').keyup(function(){
  var val = this.value;
  if(val.length<=1){
     var n = this.value.charAt(0);
     if(val && n in num2img){
       $(this).css({backgroundImage: "url(http://www.izwipe.com/change/c/data/"+n+".gif)"});
     }else{
       $(this).css({backgroundImage: "url(http://www.izwipe.com/change/c/data/1.gif)"});
     }
  }
});

^{只需在else}

中设置默认图片即可

根据输入更改图像

3 个答案: