发起会话（仅单聊）（IMBridge.startConversation)

//成功回调
var onSuccess = function(message){
    alert(message);
}

//失败回调
var onError = function(message){
    alert(message);
}

//调用方法
function startConversation(){
    var options = {
    	"targetName":"潘旭",
    	"targetId":""
	}
	var arguments = {
    	className:"IMBridge",
    	function:"startConversation",
    	params:options,
    	successCallBack:"onSuccess",
    	failCallBack:"onError"
	}
    HandBridge.postMessage(JSON.stringify(arguments));
}