Question

i am working on an adapted version of Adam Maschek’s excellent image map tool. The new functionality i have added are left/top/width/height input boxes so that you can have pixel control over the hotspot position/size. I have got it working fine in FF and Chrome but the issue i am having is in IE 7/8 where it just will not retrieve the value of the input box on change.

Here is the function where the issue is occuring:

function gui_dimension_change(e) {

function changeAreaPos(areaNum, inputVal, cssAttrib, coordPos) {
var coordsBox = document.getElementsByClassName('img_coords')[areaNum],
    newCoordsVal = coordsBox.value.split(","),
    newWidth = "",
    newHeight = "",
    imCode = imcodeContainer.value,
    pattern = imCode.match(/\d+,\d+,\d+,\d+/g);

    myimgmap.areas[areaNum].style[cssAttrib] = inputVal;

    if (cssAttrib === "left" || cssAttrib === "top") {
        myimgmap.areas[areaNum].label.style[cssAttrib] = inputVal;
        newCoordsVal[coordPos] = inputVal;
    } else if (cssAttrib === "width") {
        myimgmap.areas[areaNum].width = inputVal;
        newWidth = parseInt(newCoordsVal[0]) + parseInt(inputVal);
        newCoordsVal[coordPos] = newWidth;
    } else if (cssAttrib === "height") {
        myimgmap.areas[areaNum].height = inputVal;
        newHeight = parseInt(newCoordsVal[1]) + parseInt(inputVal);
        newCoordsVal[coordPos] = newHeight;
    }

    newCoordsVal = newCoordsVal.join(",");
    myimgmap.areas[areaNum].lastInput = newCoordsVal;
    coordsBox.value = newCoordsVal;

    imCode = imCode.replace(pattern[areaNum], newCoordsVal);
    imcodeContainer.value = imCode;

};

    // alert(this);
    // alert(this.parentNode);
    // alert(this.parentNode.id);

var inputParent = this.parentNode,
    inputVal = this.value,
    whichBox = this.name,
    areaNum = inputParent.id.replace("img_area_", ""),
    imcodeContainer = document.getElementById('html_container');

switch(whichBox)
{
    case "img_left":
        changeAreaPos(areaNum, inputVal, "left", 0);
    break;
    case "img_top":
        changeAreaPos(areaNum, inputVal, "top", 1);
    break;
    case "img_width":
        changeAreaPos(areaNum, inputVal, "width", 2);
    break;
    case "img_height":
        changeAreaPos(areaNum, inputVal, "height", 3);
    break;
}

}

The function is called like so:

myimgmap.addEvent(props[id].getElementsByTagName('input')[5], 'change', gui_dimension_change);
myimgmap.addEvent(props[id].getElementsByTagName('input')[6], 'change', gui_dimension_change);
myimgmap.addEvent(props[id].getElementsByTagName('input')[7], 'change', gui_dimension_change);
myimgmap.addEvent(props[id].getElementsByTagName('input')[8], 'change', gui_dimension_change);

So on the change event i can’t set inputParent with this.parentNode, and can’t grab the value of the input box with this.value either. Works in FF/Chrome but not IE 7/8, any ideas why IE has a problem with parentNode and getting the value?

Answer 1

OK, i figured out the solution in case anyone cares. It was all because IE handles event targets differently to other browsers, so i did the following:

var obj = (myimgmap.isMSIE) ? window.event.srcElement : e.currentTarget;

and used obj instead of this.

Stupid IE!!!