jquery: get value of custom attribute

问题

html5 supports the placeholder attribute on input[type=text] elements, but I need to handle non-compliant browsers. I know there are a thousand plugins out there for placeholder but I'd like to create the 1001st.

I am able to get a handle on the input[placeholder] element but trying to get the value of the placeholder attribute is returning undefined - $("input[placeholder]").attr("placeholder").

I'm using jquery 1.6.2.

Here is the jsfiddle. I modified the code to work in a browser that is html5 compatible just for testing purposes.

html

<input type="text" name="email" size="10" placeholder="EMAIL ADDRESS">

jquery

function SupportsInputPlaceholder() {
    var i = document.createElement("input");
    return "placeholder" in i;
}

$(document).ready(function(){
    if(!SupportsInputPlaceholder()) {
        //set initial value to placeholder attribute
        $("input[placeholder]").val($("input[placeholder]").attr("placeholder"));

        //create event handlers for focus and blur
        $("input[placeholder]").focus(function() {
            if($(this).val() == $(this).attr("placeholder")) {
                $(this).val("");
            }
        }).blur(function() {
            if($(this).val() == "") {
                $(this).val($(this).attr("placeholder"));
            }
        });
    }
});

Thanks for any and all help, B

回答1:

You need some form of iteration here, as val (except when called with a function) only works on the first element:

$("input[placeholder]").val($("input[placeholder]").attr("placeholder"));

should be:

$("input[placeholder]").each( function () {
    $(this).val( $(this).attr("placeholder") );
});

$("input[placeholder]").val(function() {
    return $(this).attr("placeholder");
});

回答2:

You can also do this by passing function with onclick event

<a onlick="getColor(this);" color="red">

<script type="text/javascript">

function getColor(el)
{
     color = $(el).attr('color');
     alert(color);
}

</script>

来源：https://stackoverflow.com/questions/7177512/jquery-get-value-of-custom-attribute

标签

jquery

custom-attributes

attr