[devnull69]

You cannot just include line breaks inside a string literal. You'll have to escape them using the \ backslash character.

    $("#localUpload").append('    <div class="file_input_div">\
        <input id="fileName" class="file_input_textbox" placeholder="No File Selected..." readonly="readonly" />\
        <input type="button" value="Browse..." class="file_input_button" /> \
        <input type="file" name="image_upload[]" id="file_upload" class="file_input_hidden" onchange="javascript: this.form.fileName.value=((this.value.replace(/^.*[\/\\]/g, "")).split("..",2));" />\
    </div>\
');