一个高效率的js脚本字符串构建类库函数

 function writeLog(text) { var txtLog = $get('txtLog'); txtLog.innerHTML+=text + '<br>'; } function runTest() { var start; var time; var text; var txtIterations = $get("txtIterations"); var nIterations=parseInt(txtIterations.value); writeLog(""); writeLog("Run Tests Append Strings (" + nIterations + ")..."); writeLog(""); var chkTestConcatWithPlus = $get("chkTestConcatWithPlus"); if (chkTestConcatWithPlus.checked) { start = new Date().getTime(); text=test1(nIterations); time = new Date().getTime() - start; writeLog("Test concatenate strings with + : " + time + " ms."); // Sys.Debug.trace(text); } start = new Date().getTime(); text=test2(nIterations); time = new Date().getTime() - start; writeLog("Test concatenate strings with Sys.StringBuilder (append) : " + time + " ms."); // Sys.Debug.trace(text); start = new Date().getTime(); text=test4(nIterations); time = new Date().getTime() - start; writeLog("Test concatenate strings with Megasoft78.StringBuilderEx (append): " + time + " ms."); // Sys.Debug.trace(text); writeLog(""); writeLog("Run Tests Append Strings with format (" + nIterations + ")..."); writeLog(""); start = new Date().getTime(); text=test3(nIterations); time = new Date().getTime() - start; writeLog("Test concatenate strings with Sys.StringBuilder (appendFormat) : " + time + " ms."); // Sys.Debug.trace(text); start = new Date().getTime(); text=test6(nIterations); time = new Date().getTime() - start; writeLog("Test concatenate strings with Megasoft78.StringBuilderEx (appendFormat): " + time + " ms."); // Sys.Debug.trace(text); start = new Date().getTime(); text=test5(nIterations); time = new Date().getTime() - start; writeLog("Test concatenate strings with Megasoft78.StringBuilderEx (appendFormat Split+Join): " + time + " ms."); // Sys.Debug.trace(text); writeLog(""); } function test1(nIterations) { var text = ""; for (var t=0;t<nIterations;t++) { text+= " Run " + t + " Run " + (t+1) + " Run " + (t+2); } return text; } function test2(nIterations) { var sb = new Sys.StringBuilder(); for (var t=0;t<nIterations;t++) { sb.append(" Run "); sb.append(t); sb.append(" Run "); sb.append(t+1); sb.append(" Run "); sb.append(t+2); } return sb.toString(); } function test3(nIterations) { var sb = new Sys.StringBuilder(); for (var t=0;t<nIterations;t++) { sb.append(String.format(" Run {0} Run {1} Run {2}", t, t+1, t+2)); } return sb.toString(); } function test4(nIterations) { var sb = new StringBuilderEx(); for (var t=0;t<nIterations;t++) { sb.append(" Run "); sb.append(t); sb.append(" Run "); sb.append(t+1); sb.append(" Run "); sb.append(t+2); } return sb.toString(); } function test5(nIterations) { var sb = new StringBuilderEx(); for (var t=0;t<nIterations;t++) { sb.appendFormatEx(" Run ? Run ? Run ?", t, t+1, t+2); } return sb.toString(); } function test6(nIterations) { var sb = new StringBuilderEx(); for (var t=0;t<nIterations;t++) { sb.appendFormat(" Run {0} Run {1} Run {2}", t, t+1, t+2); } return sb.toString(); }